<?xml version="1.0" encoding="UTF-8"?>
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <!-- XBRL Document Created with XML Edge from P3 Data Systems -->
  <roleRef roleURI="http://cassinfo.com/role/cass-cbs1" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-cbs1"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-csoi1" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-csoi1"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-csoci" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-csoci"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-csocf" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-csocf"/>
  <roleRef roleURI="http://cassinfo.com/role/InvestmentInSecuritiesScheduleOfInvestmentSecuritiesDetails" xlink:type="simple" xlink:href="cass-20201231.xsd#InvestmentInSecuritiesScheduleOfInvestmentSecuritiesDetails"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-iissofvoswuld1" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-iissofvoswuld1"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-iissoacafvoisd1" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-iissoacafvoisd1"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-paesopaed" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-paesopaed"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-ibdsoibdd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-ibdsoibdd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-ibdsoiodd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-ibdsoiodd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-ibdsomotdd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-ibdsomotdd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-csaepssocobadepsd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-csaepssocobadepsd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-ebpsoppcd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-ebpsoppcd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-ebpsospcd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-ebpsospcd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-ebpsotpaiaocld" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-ebpsotpaiaocld"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-ooesoooed" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-ooesoooed"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-itcoitebd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-itcoitebd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-itsoroeitebd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-itsoroeitebd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-itsodtaald" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-itsodtaald"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-dafvofisocfid" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-dafvofisocfid"/>
  <roleRef roleURI="http://cassinfo.com/role/RevenueFromContractsWithCustomersScheduleOfRevenueFromContractsWithCustomersDetails" xlink:type="simple" xlink:href="cass-20201231.xsd#RevenueFromContractsWithCustomersScheduleOfRevenueFromContractsWithCustomersDetails"/>
  <roleRef roleURI="http://cassinfo.com/role/LeasesScheduleOfOperatingLeaseLiabilitiesDetails" xlink:type="simple" xlink:href="cass-20201231.xsd#LeasesScheduleOfOperatingLeaseLiabilitiesDetails"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-cfiopcsocbsd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-cfiopcsocbsd"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-cfiopcsocsoid" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-cfiopcsocsoid"/>
  <roleRef roleURI="http://cassinfo.com/role/cass-cfiopcsosocfd" xlink:type="simple" xlink:href="cass-20201231.xsd#cass-cfiopcsosocfd"/>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cbs1">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets" xlink:label="locator_us-gaap_Assets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="locator_us-gaap_AvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_AvailableForSaleSecurities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="locator_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:to="locator_us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="locator_us-gaap_LoansAndLeasesReceivableAllowance"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:to="locator_us-gaap_LoansAndLeasesReceivableAllowance" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="locator_us-gaap_PropertyPlantAndEquipmentNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_PropertyPlantAndEquipmentNet" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BankOwnedLifeInsurance" xlink:label="locator_us-gaap_BankOwnedLifeInsurance"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_BankOwnedLifeInsurance" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_PaymentsInExcessOfFunding" xlink:label="locator_cass_PaymentsInExcessOfFunding"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_cass_PaymentsInExcessOfFunding" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Goodwill" xlink:label="locator_us-gaap_Goodwill"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_Goodwill" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="locator_us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_IntangibleAssetsNetExcludingGoodwill" use="optional" priority="0" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssets" xlink:label="locator_us-gaap_OtherAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_OtherAssets" use="optional" priority="0" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="locator_us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_CashAndCashEquivalentsAtCarryingValue" use="optional" priority="0" order="9" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndDueFromBanks" xlink:label="locator_us-gaap_CashAndDueFromBanks"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="locator_us-gaap_CashAndDueFromBanks" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestBearingDepositsInBanks" xlink:label="locator_us-gaap_InterestBearingDepositsInBanks"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="locator_us-gaap_InterestBearingDepositsInBanks" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_FederalFundsSoldAndOtherShortTermInvestments" xlink:label="locator_cass_FederalFundsSoldAndOtherShortTermInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:to="locator_cass_FederalFundsSoldAndOtherShortTermInvestments" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="locator_us-gaap_LiabilitiesAndStockholdersEquity"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Liabilities" xlink:label="locator_us-gaap_Liabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="locator_us-gaap_Liabilities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesNoncurrent" xlink:label="locator_us-gaap_AccountsPayableAndAccruedLiabilitiesNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Liabilities" xlink:to="locator_us-gaap_AccountsPayableAndAccruedLiabilitiesNoncurrent" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Deposits" xlink:label="locator_us-gaap_Deposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Liabilities" xlink:to="locator_us-gaap_Deposits" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestBearingDepositLiabilities" xlink:label="locator_us-gaap_NoninterestBearingDepositLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Deposits" xlink:to="locator_us-gaap_NoninterestBearingDepositLiabilities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestBearingDepositLiabilities" xlink:label="locator_us-gaap_InterestBearingDepositLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Deposits" xlink:to="locator_us-gaap_InterestBearingDepositLiabilities" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilities" xlink:label="locator_us-gaap_OtherLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Liabilities" xlink:to="locator_us-gaap_OtherLiabilities" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermBorrowings" xlink:label="locator_us-gaap_ShortTermBorrowings"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Liabilities" xlink:to="locator_us-gaap_ShortTermBorrowings" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="locator_us-gaap_StockholdersEquity"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="locator_us-gaap_StockholdersEquity" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="locator_us-gaap_PreferredStockValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_StockholdersEquity" xlink:to="locator_us-gaap_PreferredStockValue" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockValue" xlink:label="locator_us-gaap_CommonStockValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_StockholdersEquity" xlink:to="locator_us-gaap_CommonStockValue" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalCommonStock" xlink:label="locator_us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_StockholdersEquity" xlink:to="locator_us-gaap_AdditionalPaidInCapitalCommonStock" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="locator_us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_StockholdersEquity" xlink:to="locator_us-gaap_RetainedEarningsAccumulatedDeficit" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TreasuryStockValue" xlink:label="locator_us-gaap_TreasuryStockValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_StockholdersEquity" xlink:to="locator_us-gaap_TreasuryStockValue" use="optional" priority="0" order="5" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="locator_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_StockholdersEquity" xlink:to="locator_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" use="optional" priority="0" order="6" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-csoi1">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="locator_us-gaap_NetIncomeLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="locator_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetIncomeLoss" xlink:to="locator_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestExpense" xlink:label="locator_us-gaap_NoninterestExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:to="locator_us-gaap_NoninterestExpense" use="optional" priority="0" order="1" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="locator_us-gaap_LaborAndRelatedExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestExpense" xlink:to="locator_us-gaap_LaborAndRelatedExpense" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OccupancyNet" xlink:label="locator_us-gaap_OccupancyNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestExpense" xlink:to="locator_us-gaap_OccupancyNet" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquipmentExpense" xlink:label="locator_us-gaap_EquipmentExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestExpense" xlink:to="locator_us-gaap_EquipmentExpense" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="locator_us-gaap_AmortizationOfIntangibleAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestExpense" xlink:to="locator_us-gaap_AmortizationOfIntangibleAssets" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNoninterestExpense" xlink:label="locator_us-gaap_OtherNoninterestExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestExpense" xlink:to="locator_us-gaap_OtherNoninterestExpense" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues" xlink:label="locator_us-gaap_Revenues"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:to="locator_us-gaap_Revenues" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestIncome" xlink:label="locator_us-gaap_NoninterestIncome"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Revenues" xlink:to="locator_us-gaap_NoninterestIncome" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_InformationServicesPaymentAndProcessingRevenue" xlink:label="locator_cass_InformationServicesPaymentAndProcessingRevenue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestIncome" xlink:to="locator_cass_InformationServicesPaymentAndProcessingRevenue" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:label="locator_us-gaap_DebtAndEquitySecuritiesGainLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestIncome" xlink:to="locator_us-gaap_DebtAndEquitySecuritiesGainLoss" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestIncomeOther" xlink:label="locator_us-gaap_NoninterestIncomeOther"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestIncome" xlink:to="locator_us-gaap_NoninterestIncomeOther" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_BankServiceFees" xlink:label="locator_cass_BankServiceFees"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestIncome" xlink:to="locator_cass_BankServiceFees" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:label="locator_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Revenues" xlink:to="locator_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseNet" xlink:label="locator_us-gaap_InterestIncomeExpenseNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:to="locator_us-gaap_InterestIncomeExpenseNet" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestAndDividendIncomeOperating" xlink:label="locator_us-gaap_InterestAndDividendIncomeOperating"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestIncomeExpenseNet" xlink:to="locator_us-gaap_InterestAndDividendIncomeOperating" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestAndFeeIncomeLoansAndLeases" xlink:label="locator_us-gaap_InterestAndFeeIncomeLoansAndLeases"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestAndDividendIncomeOperating" xlink:to="locator_us-gaap_InterestAndFeeIncomeLoansAndLeases" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxable" xlink:label="locator_us-gaap_InterestIncomeSecuritiesTaxable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestAndDividendIncomeOperating" xlink:to="locator_us-gaap_InterestIncomeSecuritiesTaxable" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeSecuritiesTaxExempt" xlink:label="locator_us-gaap_InterestIncomeSecuritiesTaxExempt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestAndDividendIncomeOperating" xlink:to="locator_us-gaap_InterestIncomeSecuritiesTaxExempt" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_InterestOnFederalFundsSoldAndOtherShortTermInvestments" xlink:label="locator_cass_InterestOnFederalFundsSoldAndOtherShortTermInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestAndDividendIncomeOperating" xlink:to="locator_cass_InterestOnFederalFundsSoldAndOtherShortTermInvestments" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpense" xlink:label="locator_us-gaap_InterestExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestIncomeExpenseNet" xlink:to="locator_us-gaap_InterestExpense" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDeposits" xlink:label="locator_us-gaap_InterestExpenseDeposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestExpense" xlink:to="locator_us-gaap_InterestExpenseDeposits" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseShortTermBorrowings" xlink:label="locator_us-gaap_InterestExpenseShortTermBorrowings"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestExpense" xlink:to="locator_us-gaap_InterestExpenseShortTermBorrowings" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProvisionForLoanLossesExpensed" xlink:label="locator_us-gaap_ProvisionForLoanLossesExpensed"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:to="locator_us-gaap_ProvisionForLoanLossesExpensed" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="locator_us-gaap_IncomeTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetIncomeLoss" xlink:to="locator_us-gaap_IncomeTaxExpenseBenefit" use="optional" priority="0" order="2" weight="-1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-csoci">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="locator_us-gaap_ComprehensiveIncomeNetOfTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="locator_us-gaap_NetIncomeLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="locator_us-gaap_NetIncomeLoss" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_ComprehensiveIncomeNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodBeforeTax" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax" use="optional" priority="0" order="3" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesTax" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" use="optional" priority="0" order="5" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" xlink:label="locator_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:to="locator_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossArisingDuringPeriodNetOfTax" use="optional" priority="0" order="7" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-csocf">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="locator_us-gaap_NetIncomeLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_NetIncomeLoss" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepreciationAmortizationAndAccretionNet" xlink:label="locator_us-gaap_DepreciationAmortizationAndAccretionNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_DepreciationAmortizationAndAccretionNet" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="locator_us-gaap_ShareBasedCompensation"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_ShareBasedCompensation" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProvisionForLoanLossesExpensed" xlink:label="locator_us-gaap_ProvisionForLoanLossesExpensed"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_ProvisionForLoanLossesExpensed" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="locator_us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_DeferredIncomeTaxExpenseBenefit" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="locator_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInPensionPlanObligations" xlink:label="locator_us-gaap_IncreaseDecreaseInPensionPlanObligations"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInPensionPlanObligations" use="optional" priority="0" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="locator_us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInAccountsReceivable" use="optional" priority="0" order="8" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:label="locator_us-gaap_DebtAndEquitySecuritiesGainLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_DebtAndEquitySecuritiesGainLoss" use="optional" priority="0" order="9" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement" xlink:label="locator_us-gaap_OtherOperatingActivitiesCashFlowStatement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_OtherOperatingActivitiesCashFlowStatement" use="optional" priority="0" order="10" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xlink:label="locator_us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:label="locator_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:label="locator_us-gaap_PaymentsToAcquireAvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsToAcquireAvailableForSaleSecurities" use="optional" priority="0" order="3" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForProceedsFromLoansAndLeases" xlink:label="locator_us-gaap_PaymentsForProceedsFromLoansAndLeases"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsForProceedsFromLoansAndLeases" use="optional" priority="0" order="4" weight="-1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_IncreaseDecreaseInPaymentsInExcessOfFunding" xlink:label="locator_cass_IncreaseDecreaseInPaymentsInExcessOfFunding"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_cass_IncreaseDecreaseInPaymentsInExcessOfFunding" use="optional" priority="0" order="5" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="locator_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" use="optional" priority="0" order="6" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="locator_us-gaap_PaymentsToAcquireBusinessesGross"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsToAcquireBusinessesGross" use="optional" priority="0" order="7" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_IncreaseDecreaseInNonInterestBearingDemandDeposits" xlink:label="locator_cass_IncreaseDecreaseInNonInterestBearingDemandDeposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_cass_IncreaseDecreaseInNonInterestBearingDemandDeposits" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInDemandDeposits" xlink:label="locator_us-gaap_IncreaseDecreaseInDemandDeposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInDemandDeposits" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInTimeDeposits" xlink:label="locator_us-gaap_IncreaseDecreaseInTimeDeposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInTimeDeposits" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndOtherOperatingLiabilities" xlink:label="locator_us-gaap_IncreaseDecreaseInAccountsPayableAndOtherOperatingLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInAccountsPayableAndOtherOperatingLiabilities" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="locator_us-gaap_PaymentsOfDividendsCommonStock"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_PaymentsOfDividendsCommonStock" use="optional" priority="0" order="5" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="locator_us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_PaymentsForRepurchaseOfCommonStock" use="optional" priority="0" order="6" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" xlink:label="locator_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" use="optional" priority="0" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromShortTermDebt" xlink:label="locator_us-gaap_ProceedsFromShortTermDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_ProceedsFromShortTermDebt" use="optional" priority="0" order="8" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/InvestmentInSecuritiesScheduleOfInvestmentSecuritiesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesAmortizedCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="locator_us-gaap_AvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:to="locator_us-gaap_AvailableForSaleSecurities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" use="optional" priority="0" order="3" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iissofvoswuld1">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" use="optional" priority="0" order="2" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-iissoacafvoisd1">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:label="locator_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="locator_us-gaap_AvailableForSaleSecurities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecurities" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecurities" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecurities" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecurities" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue" xlink:label="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AvailableForSaleSecurities" xlink:to="locator_us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue" use="optional" priority="0" order="5" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-paesopaed">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="locator_us-gaap_PropertyPlantAndEquipmentNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="locator_us-gaap_PropertyPlantAndEquipmentGross"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="locator_us-gaap_PropertyPlantAndEquipmentGross" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="locator_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_PropertyPlantAndEquipmentNet" xlink:to="locator_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" use="optional" priority="0" order="2" weight="-1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ibdsoibdd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestBearingDepositLiabilities" xlink:label="locator_us-gaap_InterestBearingDepositLiabilities"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DemandDepositAccounts" xlink:label="locator_us-gaap_DemandDepositAccounts"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestBearingDepositLiabilities" xlink:to="locator_us-gaap_DemandDepositAccounts" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepositsSavingsDeposits" xlink:label="locator_us-gaap_DepositsSavingsDeposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestBearingDepositLiabilities" xlink:to="locator_us-gaap_DepositsSavingsDeposits" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositsLessThan100000" xlink:label="locator_us-gaap_TimeDepositsLessThan100000"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestBearingDepositLiabilities" xlink:to="locator_us-gaap_TimeDepositsLessThan100000" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_TimeDeposits100000OrMoreAndLessThan250000" xlink:label="locator_cass_TimeDeposits100000OrMoreAndLessThan250000"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestBearingDepositLiabilities" xlink:to="locator_cass_TimeDeposits100000OrMoreAndLessThan250000" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_TimeDeposits250000OrMore" xlink:label="locator_cass_TimeDeposits250000OrMore"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestBearingDepositLiabilities" xlink:to="locator_cass_TimeDeposits250000OrMore" use="optional" priority="0" order="5" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ibdsoiodd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDeposits" xlink:label="locator_us-gaap_InterestExpenseDeposits"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseDemandDepositAccounts" xlink:label="locator_us-gaap_InterestExpenseDemandDepositAccounts"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestExpenseDeposits" xlink:to="locator_us-gaap_InterestExpenseDemandDepositAccounts" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseSavingsDeposits" xlink:label="locator_us-gaap_InterestExpenseSavingsDeposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestExpenseDeposits" xlink:to="locator_us-gaap_InterestExpenseSavingsDeposits" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestExpenseTimeDepositsLessThan100000" xlink:label="locator_us-gaap_InterestExpenseTimeDepositsLessThan100000"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestExpenseDeposits" xlink:to="locator_us-gaap_InterestExpenseTimeDepositsLessThan100000" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_InterestExpenseTimeDeposits100000OrMoreAndLessThan250000" xlink:label="locator_cass_InterestExpenseTimeDeposits100000OrMoreAndLessThan250000"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestExpenseDeposits" xlink:to="locator_cass_InterestExpenseTimeDeposits100000OrMoreAndLessThan250000" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_InterestExpenseTimeDeposits250000OrMore" xlink:label="locator_cass_InterestExpenseTimeDeposits250000OrMore"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_InterestExpenseDeposits" xlink:to="locator_cass_InterestExpenseTimeDeposits250000OrMore" use="optional" priority="0" order="5" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ibdsomotdd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDeposits" xlink:label="locator_us-gaap_TimeDeposits"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositMaturitiesYearOne" xlink:label="locator_us-gaap_TimeDepositMaturitiesYearOne"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_TimeDeposits" xlink:to="locator_us-gaap_TimeDepositMaturitiesYearOne" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositMaturitiesYearTwo" xlink:label="locator_us-gaap_TimeDepositMaturitiesYearTwo"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_TimeDeposits" xlink:to="locator_us-gaap_TimeDepositMaturitiesYearTwo" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositMaturitiesYearThree" xlink:label="locator_us-gaap_TimeDepositMaturitiesYearThree"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_TimeDeposits" xlink:to="locator_us-gaap_TimeDepositMaturitiesYearThree" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositMaturitiesYearFour" xlink:label="locator_us-gaap_TimeDepositMaturitiesYearFour"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_TimeDeposits" xlink:to="locator_us-gaap_TimeDepositMaturitiesYearFour" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositMaturitiesYearFive" xlink:label="locator_us-gaap_TimeDepositMaturitiesYearFive"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_TimeDeposits" xlink:to="locator_us-gaap_TimeDepositMaturitiesYearFive" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_TimeDepositsWeightedAverageInterestRateAggregate" xlink:label="locator_cass_TimeDepositsWeightedAverageInterestRateAggregate"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearOne" xlink:label="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearOne"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_TimeDepositsWeightedAverageInterestRateAggregate" xlink:to="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearOne" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearTwo" xlink:label="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearTwo"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_TimeDepositsWeightedAverageInterestRateAggregate" xlink:to="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearTwo" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearThree" xlink:label="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearThree"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_TimeDepositsWeightedAverageInterestRateAggregate" xlink:to="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearThree" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearFour" xlink:label="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearFour"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_TimeDepositsWeightedAverageInterestRateAggregate" xlink:to="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearFour" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearFive" xlink:label="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearFive"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_TimeDepositsWeightedAverageInterestRateAggregate" xlink:to="locator_us-gaap_TimeDepositsWeightedAverageInterestRateMaturitiesYearFive" use="optional" priority="0" order="5" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-csaepssocobadepsd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="locator_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="locator_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="locator_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" xlink:label="locator_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="locator_us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment" use="optional" priority="0" order="2" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ebpsoppcd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="locator_us-gaap_DefinedBenefitPlanServiceCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="locator_us-gaap_DefinedBenefitPlanServiceCost" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="locator_us-gaap_DefinedBenefitPlanInterestCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="locator_us-gaap_DefinedBenefitPlanInterestCost" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" xlink:label="locator_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="locator_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets" use="optional" priority="0" order="3" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="locator_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="locator_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" use="optional" priority="0" order="4" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ebpsospcd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:label="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanServiceCost" xlink:label="locator_us-gaap_DefinedBenefitPlanServiceCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="locator_us-gaap_DefinedBenefitPlanServiceCost" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanInterestCost" xlink:label="locator_us-gaap_DefinedBenefitPlanInterestCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="locator_us-gaap_DefinedBenefitPlanInterestCost" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" xlink:label="locator_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost" xlink:to="locator_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit" use="optional" priority="0" order="3" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ebpsotpaiaocld">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:label="locator_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" xlink:label="locator_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:to="locator_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" xlink:label="locator_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax" xlink:to="locator_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax" use="optional" priority="0" order="2" weight="-1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-ooesoooed">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherNoninterestExpense" xlink:label="locator_us-gaap_OtherNoninterestExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SuppliesAndPostageExpense" xlink:label="locator_us-gaap_SuppliesAndPostageExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherNoninterestExpense" xlink:to="locator_us-gaap_SuppliesAndPostageExpense" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_MarketingAndAdvertisingExpense" xlink:label="locator_us-gaap_MarketingAndAdvertisingExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherNoninterestExpense" xlink:to="locator_us-gaap_MarketingAndAdvertisingExpense" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProfessionalFees" xlink:label="locator_us-gaap_ProfessionalFees"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherNoninterestExpense" xlink:to="locator_us-gaap_ProfessionalFees" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_OutsideServiceFees" xlink:label="locator_cass_OutsideServiceFees"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherNoninterestExpense" xlink:to="locator_cass_OutsideServiceFees" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InformationTechnologyAndDataProcessing" xlink:label="locator_us-gaap_InformationTechnologyAndDataProcessing"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherNoninterestExpense" xlink:to="locator_us-gaap_InformationTechnologyAndDataProcessing" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Communication" xlink:label="locator_us-gaap_Communication"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherNoninterestExpense" xlink:to="locator_us-gaap_Communication" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherExpenses" xlink:label="locator_us-gaap_OtherExpenses"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OtherNoninterestExpense" xlink:to="locator_us-gaap_OtherExpenses" use="optional" priority="0" order="7" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-itcoitebd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="locator_us-gaap_IncomeTaxExpenseBenefit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:label="locator_us-gaap_CurrentFederalTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_CurrentFederalTaxExpenseBenefit" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="locator_us-gaap_CurrentStateAndLocalTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_CurrentStateAndLocalTaxExpenseBenefit" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:label="locator_us-gaap_DeferredFederalIncomeTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_DeferredFederalIncomeTaxExpenseBenefit" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" xlink:label="locator_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit" use="optional" priority="0" order="4" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-itsoroeitebd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="locator_us-gaap_IncomeTaxExpenseBenefit"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:label="locator_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:label="locator_us-gaap_IncomeTaxReconciliationTaxExemptIncome"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_IncomeTaxReconciliationTaxExemptIncome" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:label="locator_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:label="locator_us-gaap_IncomeTaxReconciliationOtherAdjustments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_IncomeTaxReconciliationOtherAdjustments" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:label="locator_us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability" xlink:label="locator_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_IncomeTaxExpenseBenefit" xlink:to="locator_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability" use="optional" priority="0" order="6" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-itsodtaald">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="locator_us-gaap_DeferredTaxAssetsLiabilitiesNet"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsNet" xlink:label="locator_us-gaap_DeferredTaxAssetsNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:to="locator_us-gaap_DeferredTaxAssetsNet" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses" xlink:label="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsNet" xlink:to="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsProvisionForLoanLosses" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions" xlink:label="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsNet" xlink:to="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPensions" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="locator_us-gaap_OperatingLossCarryforwards"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsNet" xlink:to="locator_us-gaap_OperatingLossCarryforwards" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits" xlink:label="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsNet" xlink:to="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsPostretirementBenefits" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" xlink:label="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsNet" xlink:to="locator_us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsOther" xlink:label="locator_us-gaap_DeferredTaxAssetsOther"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsNet" xlink:to="locator_us-gaap_DeferredTaxAssetsOther" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilities" xlink:label="locator_us-gaap_DeferredTaxLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:to="locator_us-gaap_DeferredTaxLiabilities" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_DeferredTaxLiabilitiesPensionCosts" xlink:label="locator_cass_DeferredTaxLiabilitiesPensionCosts"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxLiabilities" xlink:to="locator_cass_DeferredTaxLiabilitiesPensionCosts" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" xlink:label="locator_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxLiabilities" xlink:to="locator_us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOtherFiniteLivedAssets" xlink:label="locator_us-gaap_DeferredTaxLiabilitiesOtherFiniteLivedAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxLiabilities" xlink:to="locator_us-gaap_DeferredTaxLiabilitiesOtherFiniteLivedAssets" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities" xlink:label="locator_us-gaap_DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxLiabilities" xlink:to="locator_us-gaap_DeferredTaxLiabilitiesUnrealizedGainsOnTradingSecurities" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther" xlink:label="locator_us-gaap_DeferredTaxLiabilitiesOther"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxLiabilities" xlink:to="locator_us-gaap_DeferredTaxLiabilitiesOther" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_DeferredTaxLiabilitiesStockCompensation" xlink:label="locator_cass_DeferredTaxLiabilitiesStockCompensation"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxLiabilities" xlink:to="locator_cass_DeferredTaxLiabilitiesStockCompensation" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome" xlink:label="locator_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_DeferredTaxLiabilities" xlink:to="locator_us-gaap_DeferredTaxLiabilitiesTaxDeferredIncome" use="optional" priority="0" order="7" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-dafvofisocfid">
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_AssetsCarryingAmount" xlink:label="locator_cass_AssetsCarryingAmount"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="locator_us-gaap_AvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_AssetsCarryingAmount" xlink:to="locator_us-gaap_AvailableForSaleSecurities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="locator_us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_AssetsCarryingAmount" xlink:to="locator_us-gaap_CashAndCashEquivalentsAtCarryingValue" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_AssetsCarryingAmount" xlink:to="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestReceivable" xlink:label="locator_us-gaap_InterestReceivable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_AssetsCarryingAmount" xlink:to="locator_us-gaap_InterestReceivable" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="locator_us-gaap_AssetsFairValueDisclosure"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="locator_us-gaap_InvestmentsFairValueDisclosure"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AssetsFairValueDisclosure" xlink:to="locator_us-gaap_InvestmentsFairValueDisclosure" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure" xlink:label="locator_us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AssetsFairValueDisclosure" xlink:to="locator_us-gaap_CashAndCashEquivalentsFairValueDisclosure" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure" xlink:label="locator_us-gaap_LoansReceivableFairValueDisclosure"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AssetsFairValueDisclosure" xlink:to="locator_us-gaap_LoansReceivableFairValueDisclosure" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableFairValueDisclosure" xlink:label="locator_us-gaap_AccountsReceivableFairValueDisclosure"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_AssetsFairValueDisclosure" xlink:to="locator_us-gaap_AccountsReceivableFairValueDisclosure" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_LiabilitiesCarryingValue" xlink:label="locator_cass_LiabilitiesCarryingValue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Deposits" xlink:label="locator_us-gaap_Deposits"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_LiabilitiesCarryingValue" xlink:to="locator_us-gaap_Deposits" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_AccountsAndDraftsPayable" xlink:label="locator_cass_AccountsAndDraftsPayable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_LiabilitiesCarryingValue" xlink:to="locator_cass_AccountsAndDraftsPayable" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestPayableCurrentAndNoncurrent" xlink:label="locator_us-gaap_InterestPayableCurrentAndNoncurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_LiabilitiesCarryingValue" xlink:to="locator_us-gaap_InterestPayableCurrentAndNoncurrent" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="locator_us-gaap_LiabilitiesFairValueDisclosure"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DepositsFairValueDisclosure" xlink:label="locator_us-gaap_DepositsFairValueDisclosure"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_LiabilitiesFairValueDisclosure" xlink:to="locator_us-gaap_DepositsFairValueDisclosure" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_AccountsAndDraftsPayableFairValueDisclosure" xlink:label="locator_cass_AccountsAndDraftsPayableFairValueDisclosure"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_LiabilitiesFairValueDisclosure" xlink:to="locator_cass_AccountsAndDraftsPayableFairValueDisclosure" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccruedLiabilitiesFairValueDisclosure" xlink:label="locator_us-gaap_AccruedLiabilitiesFairValueDisclosure"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_LiabilitiesFairValueDisclosure" xlink:to="locator_us-gaap_AccruedLiabilitiesFairValueDisclosure" use="optional" priority="0" order="3" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/RevenueFromContractsWithCustomersScheduleOfRevenueFromContractsWithCustomersDetails">
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_FeeRevenueInscopeFASBASC606" xlink:label="locator_cass_FeeRevenueInscopeFASBASC606"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_InformationServicesPaymentAndProcessingRevenue" xlink:label="locator_cass_InformationServicesPaymentAndProcessingRevenue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_FeeRevenueInscopeFASBASC606" xlink:to="locator_cass_InformationServicesPaymentAndProcessingRevenue" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_BankServiceFees" xlink:label="locator_cass_BankServiceFees"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_FeeRevenueInscopeFASBASC606" xlink:to="locator_cass_BankServiceFees" use="optional" priority="0" order="2" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/LeasesScheduleOfOperatingLeaseLiabilitiesDetails">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:label="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDue"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" xlink:label="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDue" xlink:to="locator_us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter" use="optional" priority="0" order="6" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cfiopcsocbsd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Assets" xlink:label="locator_us-gaap_Assets"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashAndDueFromBanks" xlink:label="locator_us-gaap_CashAndDueFromBanks"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_CashAndDueFromBanks" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherShortTermInvestments" xlink:label="locator_us-gaap_OtherShortTermInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_OtherShortTermInvestments" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="locator_us-gaap_AvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_AvailableForSaleSecurities" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_LoansAndLeasesReceivableNetReportedAmount" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:label="locator_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="locator_us-gaap_PropertyPlantAndEquipmentNet"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_PropertyPlantAndEquipmentNet" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherAssets" xlink:label="locator_us-gaap_OtherAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_us-gaap_OtherAssets" use="optional" priority="0" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_PaymentsInExcessOfFunding" xlink:label="locator_cass_PaymentsInExcessOfFunding"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Assets" xlink:to="locator_cass_PaymentsInExcessOfFunding" use="optional" priority="0" order="8" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Liabilities" xlink:label="locator_us-gaap_Liabilities"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_AccountsAndDraftsPayable" xlink:label="locator_cass_AccountsAndDraftsPayable"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Liabilities" xlink:to="locator_cass_AccountsAndDraftsPayable" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherLiabilities" xlink:label="locator_us-gaap_OtherLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Liabilities" xlink:to="locator_us-gaap_OtherLiabilities" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShortTermBorrowings" xlink:label="locator_us-gaap_ShortTermBorrowings"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Liabilities" xlink:to="locator_us-gaap_ShortTermBorrowings" use="optional" priority="0" order="3" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cfiopcsocsoid">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Revenues" xlink:label="locator_us-gaap_Revenues"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentIncomeNonoperating" xlink:label="locator_us-gaap_InvestmentIncomeNonoperating"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Revenues" xlink:to="locator_us-gaap_InvestmentIncomeNonoperating" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:label="locator_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Revenues" xlink:to="locator_us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherIncome" xlink:label="locator_us-gaap_OtherIncome"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Revenues" xlink:to="locator_us-gaap_OtherIncome" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:label="locator_us-gaap_DebtAndEquitySecuritiesGainLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Revenues" xlink:to="locator_us-gaap_DebtAndEquitySecuritiesGainLoss" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_InformationServicesPaymentAndProcessingRevenue" xlink:label="locator_cass_InformationServicesPaymentAndProcessingRevenue"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_Revenues" xlink:to="locator_cass_InformationServicesPaymentAndProcessingRevenue" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoninterestExpense" xlink:label="locator_us-gaap_NoninterestExpense"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="locator_us-gaap_LaborAndRelatedExpense"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestExpense" xlink:to="locator_us-gaap_LaborAndRelatedExpense" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherExpenses" xlink:label="locator_us-gaap_OtherExpenses"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NoninterestExpense" xlink:to="locator_us-gaap_OtherExpenses" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="locator_us-gaap_NetIncomeLoss"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_IncomeBeforeUndistributedIncomeOfSubsidiaries" xlink:label="locator_cass_IncomeBeforeUndistributedIncomeOfSubsidiaries"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetIncomeLoss" xlink:to="locator_cass_IncomeBeforeUndistributedIncomeOfSubsidiaries" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="locator_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_IncomeBeforeUndistributedIncomeOfSubsidiaries" xlink:to="locator_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="locator_us-gaap_IncomeTaxExpenseBenefit"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_cass_IncomeBeforeUndistributedIncomeOfSubsidiaries" xlink:to="locator_us-gaap_IncomeTaxExpenseBenefit" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="locator_us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetIncomeLoss" xlink:to="locator_us-gaap_IncomeLossFromEquityMethodInvestments" use="optional" priority="0" order="2" weight="1"/>
  </calculationLink>
  <calculationLink xlink:type="extended" xlink:role="http://cassinfo.com/role/cass-cfiopcsosocfd">
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:label="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="locator_us-gaap_NetIncomeLoss"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_NetIncomeLoss" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="locator_us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_IncomeLossFromEquityMethodInvestments" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="locator_us-gaap_IncreaseDecreaseInOtherOperatingAssets"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInOtherOperatingAssets" use="optional" priority="0" order="3" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="locator_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentForAmortization" xlink:label="locator_us-gaap_AdjustmentForAmortization"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_AdjustmentForAmortization" use="optional" priority="0" order="5" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement" xlink:label="locator_us-gaap_OtherOperatingActivitiesCashFlowStatement"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_OtherOperatingActivitiesCashFlowStatement" use="optional" priority="0" order="6" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="locator_us-gaap_ShareBasedCompensation"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="locator_us-gaap_ShareBasedCompensation" use="optional" priority="0" order="7" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" use="optional" priority="0" order="2" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:label="locator_us-gaap_PaymentsToAcquireAvailableForSaleSecurities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsToAcquireAvailableForSaleSecurities" use="optional" priority="0" order="1" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForProceedsFromLoansAndLeases" xlink:label="locator_us-gaap_PaymentsForProceedsFromLoansAndLeases"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsForProceedsFromLoansAndLeases" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="locator_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" use="optional" priority="0" order="3" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="locator_us-gaap_PaymentsToAcquireBusinessesGross"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_us-gaap_PaymentsToAcquireBusinessesGross" use="optional" priority="0" order="4" weight="-1"/>
    <loc xlink:type="locator" xlink:href="cass-20201231.xsd#cass_IncreaseDecreaseInPaymentsInExcessOfFunding" xlink:label="locator_cass_IncreaseDecreaseInPaymentsInExcessOfFunding"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="locator_cass_IncreaseDecreaseInPaymentsInExcessOfFunding" use="optional" priority="0" order="5" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect" xlink:to="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" use="optional" priority="0" order="3" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsPayableAndOtherOperatingLiabilities" xlink:label="locator_us-gaap_IncreaseDecreaseInAccountsPayableAndOtherOperatingLiabilities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_IncreaseDecreaseInAccountsPayableAndOtherOperatingLiabilities" use="optional" priority="0" order="1" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="locator_us-gaap_PaymentsOfDividendsCommonStock"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_PaymentsOfDividendsCommonStock" use="optional" priority="0" order="2" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="locator_us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_PaymentsForRepurchaseOfCommonStock" use="optional" priority="0" order="3" weight="-1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" xlink:label="locator_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_ProceedsFromPaymentsForOtherFinancingActivities" use="optional" priority="0" order="4" weight="1"/>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromShortTermDebt" xlink:label="locator_us-gaap_ProceedsFromShortTermDebt"/>
    <calculationArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="locator_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="locator_us-gaap_ProceedsFromShortTermDebt" use="optional" priority="0" order="5" weight="1"/>
  </calculationLink>
</linkbase>
