<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.4b -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Cover" roleURI="http://oceanpowertechnologies.com/role/Cover" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#BalanceSheets" roleURI="http://oceanpowertechnologies.com/role/BalanceSheets" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#BalanceSheetsParenthetical" roleURI="http://oceanpowertechnologies.com/role/BalanceSheetsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#StatementsOfOperations" roleURI="http://oceanpowertechnologies.com/role/StatementsOfOperations" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#StatementsOfShareholdersEquity" roleURI="http://oceanpowertechnologies.com/role/StatementsOfShareholdersEquity" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#StatementsOfCashFlows" roleURI="http://oceanpowertechnologies.com/role/StatementsOfCashFlows" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#BackgroundBasisOfPresentationAndLiquidity" roleURI="http://oceanpowertechnologies.com/role/BackgroundBasisOfPresentationAndLiquidity" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#SummaryOfSignificantAccountingPolicies" roleURI="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#AccountsReceivableContractAssetsAndContractLiabilities" roleURI="http://oceanpowertechnologies.com/role/AccountsReceivableContractAssetsAndContractLiabilities" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Inventory" roleURI="http://oceanpowertechnologies.com/role/Inventory" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#OtherCurrentAssets" roleURI="http://oceanpowertechnologies.com/role/OtherCurrentAssets" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#PropertyAndEquipmentNet" roleURI="http://oceanpowertechnologies.com/role/PropertyAndEquipmentNet" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#IntangibleAssets" roleURI="http://oceanpowertechnologies.com/role/IntangibleAssets" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Goodwill" roleURI="http://oceanpowertechnologies.com/role/Goodwill" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Leases" roleURI="http://oceanpowertechnologies.com/role/Leases" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#AccruedExpenses" roleURI="http://oceanpowertechnologies.com/role/AccruedExpenses" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Share-basedCompensation" roleURI="http://oceanpowertechnologies.com/role/Share-basedCompensation" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#FairValueMeasurements" roleURI="http://oceanpowertechnologies.com/role/FairValueMeasurements" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Equity" roleURI="http://oceanpowertechnologies.com/role/Equity" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#CommitmentsAndContingencies" roleURI="http://oceanpowertechnologies.com/role/CommitmentsAndContingencies" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#IncomeTaxes" roleURI="http://oceanpowertechnologies.com/role/IncomeTaxes" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#OperatingSegmentsAndGeographicInformation" roleURI="http://oceanpowertechnologies.com/role/OperatingSegmentsAndGeographicInformation" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#SummaryOfSignificantAccountingPoliciesPolicies" roleURI="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPoliciesPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#SummaryOfSignificantAccountingPoliciesTables" roleURI="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPoliciesTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#AccountsReceivableContractAssetsAndContractLiabilitiesTables" roleURI="http://oceanpowertechnologies.com/role/AccountsReceivableContractAssetsAndContractLiabilitiesTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#InventoryTables" roleURI="http://oceanpowertechnologies.com/role/InventoryTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#OtherCurrentAssetsTables" roleURI="http://oceanpowertechnologies.com/role/OtherCurrentAssetsTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#PropertyAndEquipmentNetTables" roleURI="http://oceanpowertechnologies.com/role/PropertyAndEquipmentNetTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#IntangibleAssetsTables" roleURI="http://oceanpowertechnologies.com/role/IntangibleAssetsTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#LeasesTables" roleURI="http://oceanpowertechnologies.com/role/LeasesTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#AccruedExpensesTables" roleURI="http://oceanpowertechnologies.com/role/AccruedExpensesTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Share-basedCompensationTables" roleURI="http://oceanpowertechnologies.com/role/Share-basedCompensationTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#FairValueMeasurementsTables" roleURI="http://oceanpowertechnologies.com/role/FairValueMeasurementsTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#OperatingSegmentsAndGeographicInformationTables" roleURI="http://oceanpowertechnologies.com/role/OperatingSegmentsAndGeographicInformationTables" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#BackgroundBasisOfPresentationAndLiquidityDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/BackgroundBasisOfPresentationAndLiquidityDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfCashCashEquivalentsAndRestrictedCashDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfCashCashEquivalentsAndRestrictedCashDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfPropertyAndEquipmentEstimatedUsefulLifeDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfPropertyAndEquipmentEstimatedUsefulLifeDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfRevenueRecognizedUnderAsc606AndAsc842Details" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfRevenueRecognizedUnderAsc606AndAsc842Details" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#SummaryOfSignificantAccountingPoliciesDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPoliciesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfAccountsReceivableContractAssetsAndContractLiabilitiesDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfAccountsReceivableContractAssetsAndContractLiabilitiesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfSignificantChangesInContractAssetsDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfSignificantChangesInContractAssetsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfSignificantChangesInContractLiabilitiesDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfSignificantChangesInContractLiabilitiesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfInventoryDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfInventoryDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfOtherCurrentAssetsDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfOtherCurrentAssetsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#OtherCurrentAssetsDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/OtherCurrentAssetsDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfComponentsOfPropertyAndEquipmentNetDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfComponentsOfPropertyAndEquipmentNetDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#PropertyAndEquipmentNetDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/PropertyAndEquipmentNetDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfComponentsOfIntangibleAssetsDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfComponentsOfIntangibleAssetsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#IntangibleAssetsDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/IntangibleAssetsDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#GoodwillDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/GoodwillDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfOperatingLeaseCostsDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfOperatingLeaseCostsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfRight-ofUseAssetsAndLeaseLiabilitiesDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfRight-ofUseAssetsAndLeaseLiabilitiesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfFutureMinimumLeasePaymentsUnderOperatingLeaseDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfFutureMinimumLeasePaymentsUnderOperatingLeaseDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#LeasesDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/LeasesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfAccruedExpensesDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfAccruedExpensesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfStockOptionActivityDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfStockOptionActivityDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfPerformanceStockUnitsDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfPerformanceStockUnitsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfNon-vestedRestrictedStockActivityDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfNon-vestedRestrictedStockActivityDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#Share-basedCompensationDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/Share-basedCompensationDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfFairValueAssetsOnRecurringBasisDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfFairValueAssetsOnRecurringBasisDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#EquityDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/EquityDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#IncomeTaxesDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/IncomeTaxesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#ScheduleOfOperatingSegmentExpensesDetails" roleURI="http://oceanpowertechnologies.com/role/ScheduleOfOperatingSegmentExpensesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="optt-20260131.xsd#OperatingSegmentsAndGeographicInformationDetailsNarrative" roleURI="http://oceanpowertechnologies.com/role/OperatingSegmentsAndGeographicInformationDetailsNarrative" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Cover" xlink:title="00000001 - Document - Cover" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/BalanceSheets" xlink:title="00000002 - Statement - Consolidated Balance Sheets">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaapAssetsCurrent" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetCurrent" xlink:label="loc_us-gaapAccountsReceivableNetCurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapAccountsReceivableNetCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerAssetNetCurrent" xlink:label="loc_us-gaapContractWithCustomerAssetNetCurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapContractWithCustomerAssetNetCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaapInventoryNet" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapInventoryNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaapOtherAssetsCurrent" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapOtherAssetsCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets" xlink:label="loc_us-gaapAssets" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapAssetsCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapPropertyPlantAndEquipmentNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaapIntangibleAssetsNetExcludingGoodwill" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapIntangibleAssetsNetExcludingGoodwill" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaapOperatingLeaseRightOfUseAsset" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapOperatingLeaseRightOfUseAsset" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCashNoncurrent" xlink:label="loc_us-gaapRestrictedCashNoncurrent" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapRestrictedCashNoncurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaapGoodwill" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssets" xlink:to="loc_us-gaapGoodwill" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaapLiabilitiesCurrent" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaapAccountsPayableCurrent" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapAccountsPayableCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_EarnOutPayableCurrent" xlink:label="loc_OPTTEarnOutPayableCurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_OPTTEarnOutPayableCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConvertibleNotesPayableCurrent" xlink:label="loc_us-gaapConvertibleNotesPayableCurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapConvertibleNotesPayableCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilitiesCurrent" xlink:label="loc_us-gaapDerivativeLiabilitiesCurrent" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapDerivativeLiabilitiesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaapAccruedLiabilitiesCurrent" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapAccruedLiabilitiesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaapOperatingLeaseLiabilityCurrent" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapOperatingLeaseLiabilityCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaapContractWithCustomerLiabilityCurrent" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapContractWithCustomerLiabilityCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities" xlink:label="loc_us-gaapLiabilities" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapLiabilitiesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredIncomeTaxLiabilitiesNet" xlink:label="loc_us-gaapDeferredIncomeTaxLiabilitiesNet" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapDeferredIncomeTaxLiabilitiesNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="loc_us-gaapOperatingLeaseLiabilityNoncurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapOperatingLeaseLiabilityNoncurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaapPreferredStockValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapPreferredStockValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue" xlink:label="loc_us-gaapCommonStockValue" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapCommonStockValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValue" xlink:label="loc_us-gaapTreasuryStockValue" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapTreasuryStockValue" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaapAdditionalPaidInCapital" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapAdditionalPaidInCapital" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaapAccumulatedOtherComprehensiveIncomeLossNetOfTax" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapStockholdersEquity" xlink:to="loc_us-gaapAccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="loc_us-gaapLiabilitiesAndStockholdersEquity" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies" xlink:label="loc_us-gaapCommitmentsAndContingencies" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapCommitmentsAndContingencies" xlink:type="arc" weight="1" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapStockholdersEquity" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/BalanceSheetsParenthetical" xlink:title="00000003 - Statement - Consolidated Balance Sheets (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/StatementsOfOperations" xlink:title="00000004 - Statement - Consolidated Statements of Operations (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaapGrossProfit" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues" xlink:label="loc_us-gaapRevenues" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapGrossProfit" xlink:to="loc_us-gaapRevenues" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaapCostOfRevenue" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapGrossProfit" xlink:to="loc_us-gaapCostOfRevenue" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss" xlink:label="loc_us-gaapOperatingIncomeLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingIncomeLoss" xlink:to="loc_us-gaapGrossProfit" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaapOperatingExpenses" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingIncomeLoss" xlink:to="loc_us-gaapOperatingExpenses" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapOperatingIncomeLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNet" xlink:label="loc_us-gaapInterestIncomeExpenseNet" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapInterestIncomeExpenseNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense" xlink:label="loc_us-gaapOtherNonoperatingIncomeExpense" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapOtherNonoperatingIncomeExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_ChangeInFairValueOfDerivative" xlink:label="loc_OPTTChangeInFairValueOfDerivative" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_OPTTChangeInFairValueOfDerivative" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaapGainsLossesOnExtinguishmentOfDebt" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapGainsLossesOnExtinguishmentOfDebt" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignCurrencyTransactionGainLossBeforeTax" xlink:label="loc_us-gaapForeignCurrencyTransactionGainLossBeforeTax" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapForeignCurrencyTransactionGainLossBeforeTax" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaapIncomeTaxExpenseBenefit" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapIncomeTaxExpenseBenefit" xlink:type="arc" weight="-1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/StatementsOfShareholdersEquity" xlink:title="00000005 - Statement - Consolidated Statements of Shareholders&apos; Equity (Unaudited)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/StatementsOfCashFlows" xlink:title="00000006 - Statement - Consolidated Statements of Cash Flows (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapNetIncomeLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaapDepreciation" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapDepreciation" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_ForeignCurrencyTransactionGainLossNetOfTax" xlink:label="loc_OPTTForeignCurrencyTransactionGainLossNetOfTax" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_OPTTForeignCurrencyTransactionGainLossNetOfTax" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="loc_us-gaapGainLossOnSaleOfPropertyPlantEquipment" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapGainLossOnSaleOfPropertyPlantEquipment" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaapAmortizationOfIntangibleAssets" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapAmortizationOfIntangibleAssets" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense" xlink:label="loc_us-gaapOperatingLeaseRightOfUseAssetAmortizationExpense" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapOperatingLeaseRightOfUseAssetAmortizationExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaapShareBasedCompensation" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapShareBasedCompensation" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_ChangeInFairValueOfDerivative" xlink:label="loc_OPTTChangeInFairValueOfDerivative" />
      <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_OPTTChangeInFairValueOfDerivative" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfOtherAssets" xlink:label="loc_us-gaapGainLossOnSaleOfOtherAssets" />
      <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapGainLossOnSaleOfOtherAssets" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaapIncreaseDecreaseInAccountsReceivable" />
      <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccountsReceivable" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerAsset" xlink:label="loc_us-gaapIncreaseDecreaseInContractWithCustomerAsset" />
      <link:calculationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInContractWithCustomerAsset" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInInventories" xlink:label="loc_us-gaapIncreaseDecreaseInInventories" />
      <link:calculationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInInventories" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingAssets" xlink:label="loc_us-gaapIncreaseDecreaseInOtherOperatingAssets" />
      <link:calculationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInOtherOperatingAssets" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaapIncreaseDecreaseInAccountsPayable" />
      <link:calculationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccountsPayable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherOperatingLiabilities" xlink:label="loc_us-gaapIncreaseDecreaseInOtherOperatingLiabilities" />
      <link:calculationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInOtherOperatingLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities" xlink:label="loc_us-gaapIncreaseDecreaseInAccruedLiabilities" />
      <link:calculationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccruedLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability" xlink:label="loc_us-gaapIncreaseDecreaseInOperatingLeaseLiability" />
      <link:calculationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInOperatingLeaseLiability" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:label="loc_us-gaapIncreaseDecreaseInContractWithCustomerLiability" />
      <link:calculationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInContractWithCustomerLiability" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:label="loc_us-gaapPaymentsToAcquirePropertyPlantAndEquipment" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:to="loc_us-gaapPaymentsToAcquirePropertyPlantAndEquipment" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaapPaymentsRelatedToTaxWithholdingForShareBasedCompensation" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapPaymentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromConvertibleDebt" xlink:label="loc_us-gaapProceedsFromConvertibleDebt" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromConvertibleDebt" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceInitialPublicOffering" xlink:label="loc_us-gaapProceedsFromIssuanceInitialPublicOffering" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromIssuanceInitialPublicOffering" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfCommonStock" xlink:label="loc_us-gaapProceedsFromIssuanceOfCommonStock" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromIssuanceOfCommonStock" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:label="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:type="arc" weight="1" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" xlink:type="arc" weight="1" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/BackgroundBasisOfPresentationAndLiquidity" xlink:title="999007 - Disclosure - Background, Basis of Presentation and Liquidity" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPolicies" xlink:title="999008 - Disclosure - Summary of Significant Accounting Policies" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/AccountsReceivableContractAssetsAndContractLiabilities" xlink:title="999009 - Disclosure - Accounts Receivable, Contract Assets and Contract Liabilities" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Inventory" xlink:title="999010 - Disclosure - Inventory" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/OtherCurrentAssets" xlink:title="999011 - Disclosure - Other Current Assets" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/PropertyAndEquipmentNet" xlink:title="999012 - Disclosure - Property and Equipment, net" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/IntangibleAssets" xlink:title="999013 - Disclosure - Intangible Assets" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Goodwill" xlink:title="999014 - Disclosure - Goodwill" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Leases" xlink:title="999015 - Disclosure - Leases" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/AccruedExpenses" xlink:title="999016 - Disclosure - Accrued Expenses" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Share-basedCompensation" xlink:title="999017 - Disclosure - Share-Based Compensation" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/FairValueMeasurements" xlink:title="999018 - Disclosure - Fair Value Measurements" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Equity" xlink:title="999019 - Disclosure - Equity" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/CommitmentsAndContingencies" xlink:title="999020 - Disclosure - Commitments and Contingencies" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/IncomeTaxes" xlink:title="999021 - Disclosure - Income Taxes" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/OperatingSegmentsAndGeographicInformation" xlink:title="999022 - Disclosure - Operating Segments and Geographic Information" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="999023 - Disclosure - Summary of Significant Accounting Policies (Policies)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPoliciesTables" xlink:title="999024 - Disclosure - Summary of Significant Accounting Policies (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/AccountsReceivableContractAssetsAndContractLiabilitiesTables" xlink:title="999025 - Disclosure - Accounts Receivable, Contract Assets and Contract Liabilities (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/InventoryTables" xlink:title="999026 - Disclosure - Inventory (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/OtherCurrentAssetsTables" xlink:title="999027 - Disclosure - Other Current Assets (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/PropertyAndEquipmentNetTables" xlink:title="999028 - Disclosure - Property and Equipment, net (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/IntangibleAssetsTables" xlink:title="999029 - Disclosure - Intangible Assets (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/LeasesTables" xlink:title="999030 - Disclosure - Leases (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/AccruedExpensesTables" xlink:title="999031 - Disclosure - Accrued Expenses (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Share-basedCompensationTables" xlink:title="999032 - Disclosure - Share-Based Compensation (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/FairValueMeasurementsTables" xlink:title="999033 - Disclosure - Fair Value Measurements (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/OperatingSegmentsAndGeographicInformationTables" xlink:title="999034 - Disclosure - Operating Segments and Geographic Information (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/BackgroundBasisOfPresentationAndLiquidityDetailsNarrative" xlink:title="999035 - Disclosure - Background, Basis of Presentation and Liquidity (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfCashCashEquivalentsAndRestrictedCashDetails" xlink:title="999036 - Disclosure - Schedule of Cash, Cash Equivalents and Restricted Cash (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:label="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue" xlink:label="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="loc_us-gaapCashAndCashEquivalentsAtCarryingValue" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedCash" xlink:label="loc_us-gaapRestrictedCash" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents" xlink:to="loc_us-gaapRestrictedCash" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfPropertyAndEquipmentEstimatedUsefulLifeDetails" xlink:title="999037 - Disclosure - Schedule of Property and Equipment Estimated Useful Life (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfRevenueRecognizedUnderAsc606AndAsc842Details" xlink:title="999038 - Disclosure - Schedule of Revenue Recognized Under ASC 606 and ASC 842 (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/SummaryOfSignificantAccountingPoliciesDetailsNarrative" xlink:title="999039 - Disclosure - Summary of Significant Accounting Policies (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfAccountsReceivableContractAssetsAndContractLiabilitiesDetails" xlink:title="999040 - Disclosure - Schedule of Accounts Receivable, Contract Assets and Contract Liabilities (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfSignificantChangesInContractAssetsDetails" xlink:title="999041 - Disclosure - Schedule of Significant Changes in Contract Assets (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerAsset" xlink:label="loc_us-gaapIncreaseDecreaseInContractWithCustomerAsset" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerAssetReclassifiedToReceivable" xlink:label="loc_us-gaapContractWithCustomerAssetReclassifiedToReceivable" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncreaseDecreaseInContractWithCustomerAsset" xlink:to="loc_us-gaapContractWithCustomerAssetReclassifiedToReceivable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_RevenueRecognizedAndNotBilled" xlink:label="loc_OPTTRevenueRecognizedAndNotBilled" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncreaseDecreaseInContractWithCustomerAsset" xlink:to="loc_OPTTRevenueRecognizedAndNotBilled" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfSignificantChangesInContractLiabilitiesDetails" xlink:title="999042 - Disclosure - Schedule of Significant Changes in Contract Liabilities (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:label="loc_us-gaapIncreaseDecreaseInContractWithCustomerLiability" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_ContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance" xlink:label="loc_OPTTContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncreaseDecreaseInContractWithCustomerLiability" xlink:to="loc_OPTTContractWithCustomerLiabilityRevenueRecognizedIncludingOpeningBalance" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_PaymentsCollectedForWhichRevenueHasNotBeenRecognized" xlink:label="loc_OPTTPaymentsCollectedForWhichRevenueHasNotBeenRecognized" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncreaseDecreaseInContractWithCustomerLiability" xlink:to="loc_OPTTPaymentsCollectedForWhichRevenueHasNotBeenRecognized" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfInventoryDetails" xlink:title="999043 - Disclosure - Schedule of Inventory (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet" xlink:label="loc_us-gaapInventoryNet" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryRawMaterials" xlink:label="loc_us-gaapInventoryRawMaterials" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInventoryNet" xlink:to="loc_us-gaapInventoryRawMaterials" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryWorkInProcess" xlink:label="loc_us-gaapInventoryWorkInProcess" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInventoryNet" xlink:to="loc_us-gaapInventoryWorkInProcess" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryFinishedGoods" xlink:label="loc_us-gaapInventoryFinishedGoods" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapInventoryNet" xlink:to="loc_us-gaapInventoryFinishedGoods" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfOtherCurrentAssetsDetails" xlink:title="999044 - Disclosure - Schedule of Other Current Assets (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaapOtherAssetsCurrent" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidInsurance" xlink:label="loc_us-gaapPrepaidInsurance" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherAssetsCurrent" xlink:to="loc_us-gaapPrepaidInsurance" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_PrepaidSoftwareAndLicenses" xlink:label="loc_OPTTPrepaidSoftwareAndLicenses" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherAssetsCurrent" xlink:to="loc_OPTTPrepaidSoftwareAndLicenses" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_PrepaidSalesAndMarketing" xlink:label="loc_OPTTPrepaidSalesAndMarketing" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherAssetsCurrent" xlink:to="loc_OPTTPrepaidSalesAndMarketing" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_PrepaidProjectCosts" xlink:label="loc_OPTTPrepaidProjectCosts" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherAssetsCurrent" xlink:to="loc_OPTTPrepaidProjectCosts" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_PrepaidInventory" xlink:label="loc_OPTTPrepaidInventory" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherAssetsCurrent" xlink:to="loc_OPTTPrepaidInventory" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPrepaidExpenseCurrent" xlink:label="loc_us-gaapOtherPrepaidExpenseCurrent" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOtherAssetsCurrent" xlink:to="loc_us-gaapOtherPrepaidExpenseCurrent" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/OtherCurrentAssetsDetailsNarrative" xlink:title="999045 - Disclosure - Other Current Assets (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfComponentsOfPropertyAndEquipmentNetDetails" xlink:title="999046 - Disclosure - Schedule of Components of Property and Equipment, Net (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaapPropertyPlantAndEquipmentGross" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapPropertyPlantAndEquipmentNet" xlink:to="loc_us-gaapPropertyPlantAndEquipmentGross" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaapAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapPropertyPlantAndEquipmentNet" xlink:to="loc_us-gaapAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:type="arc" weight="-1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/PropertyAndEquipmentNetDetailsNarrative" xlink:title="999047 - Disclosure - Property and Equipment, net (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfComponentsOfIntangibleAssetsDetails" xlink:title="999048 - Disclosure - Schedule of Components of Intangible Assets (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsGross" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedPatentsGross" xlink:label="loc_us-gaapFiniteLivedPatentsGross" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsGross" xlink:to="loc_us-gaapFiniteLivedPatentsGross" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedTrademarksGross" xlink:label="loc_us-gaapFiniteLivedTrademarksGross" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsGross" xlink:to="loc_us-gaapFiniteLivedTrademarksGross" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsNet" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsGross" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaapFiniteLivedIntangibleAssetsAccumulatedAmortization" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapFiniteLivedIntangibleAssetsNet" xlink:to="loc_us-gaapFiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:type="arc" weight="-1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/IntangibleAssetsDetailsNarrative" xlink:title="999049 - Disclosure - Intangible Assets (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/GoodwillDetailsNarrative" xlink:title="999050 - Disclosure - Goodwill (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfOperatingLeaseCostsDetails" xlink:title="999051 - Disclosure - Schedule of Operating Lease Costs (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseCost" xlink:label="loc_us-gaapLeaseCost" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseCost" xlink:label="loc_us-gaapOperatingLeaseCost" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLeaseCost" xlink:to="loc_us-gaapOperatingLeaseCost" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermLeaseCost" xlink:label="loc_us-gaapShortTermLeaseCost" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLeaseCost" xlink:to="loc_us-gaapShortTermLeaseCost" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfRight-ofUseAssetsAndLeaseLiabilitiesDetails" xlink:title="999052 - Disclosure - Schedule of Right-of use Assets and Lease Liabilities (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaapOperatingLeaseLiability" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaapOperatingLeaseLiabilityCurrent" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingLeaseLiability" xlink:to="loc_us-gaapOperatingLeaseLiabilityCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="loc_us-gaapOperatingLeaseLiabilityNoncurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingLeaseLiability" xlink:to="loc_us-gaapOperatingLeaseLiabilityNoncurrent" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfFutureMinimumLeasePaymentsUnderOperatingLeaseDetails" xlink:title="999053 - Disclosure - Schedule of Future Minimum Lease Payments Under Operating Lease (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearTwo" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearThree" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:label="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearFour" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" xlink:label="loc_OPTTLesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLesseeOperatingLeaseLiabilityPaymentsDue" xlink:to="loc_OPTTLesseeOperatingLeaseLiabilityPaymentsDueAfterYearFour" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/LeasesDetailsNarrative" xlink:title="999054 - Disclosure - Leases (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfAccruedExpensesDetails" xlink:title="999055 - Disclosure - Schedule of Accrued Expenses (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaapAccruedLiabilitiesCurrent" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherEmployeeRelatedLiabilitiesCurrent" xlink:label="loc_us-gaapOtherEmployeeRelatedLiabilitiesCurrent" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesCurrent" xlink:to="loc_us-gaapOtherEmployeeRelatedLiabilitiesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedSalariesCurrent" xlink:label="loc_us-gaapAccruedSalariesCurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesCurrent" xlink:to="loc_us-gaapAccruedSalariesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedProfessionalFeesCurrent" xlink:label="loc_us-gaapAccruedProfessionalFeesCurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesCurrent" xlink:to="loc_us-gaapAccruedProfessionalFeesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_AccruedProjectCosts" xlink:label="loc_OPTTAccruedProjectCosts" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesCurrent" xlink:to="loc_OPTTAccruedProjectCosts" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestPayableCurrent" xlink:label="loc_us-gaapInterestPayableCurrent" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesCurrent" xlink:to="loc_us-gaapInterestPayableCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaapOtherAccruedLiabilitiesCurrent" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesCurrent" xlink:to="loc_us-gaapOtherAccruedLiabilitiesCurrent" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfStockOptionActivityDetails" xlink:title="999056 - Disclosure - Schedule of Stock Option Activity (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfPerformanceStockUnitsDetails" xlink:title="999057 - Disclosure - Schedule of Performance Stock Units (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfNon-vestedRestrictedStockActivityDetails" xlink:title="999058 - Disclosure - Schedule of Non-vested Restricted Stock Activity (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/Share-basedCompensationDetailsNarrative" xlink:title="999059 - Disclosure - Share-Based Compensation (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfFairValueAssetsOnRecurringBasisDetails" xlink:title="999060 - Disclosure - Schedule of Fair Value Assets on Recurring Basis (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/EquityDetailsNarrative" xlink:title="999061 - Disclosure - Equity (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/IncomeTaxesDetailsNarrative" xlink:title="999062 - Disclosure - Income Taxes (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/ScheduleOfOperatingSegmentExpensesDetails" xlink:title="999063 - Disclosure - Schedule of Operating Segment Expenses (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Revenues" xlink:label="loc_us-gaapRevenues" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapRevenues" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfRevenue" xlink:label="loc_us-gaapCostOfRevenue" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapCostOfRevenue" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherCostAndExpenseOperating" xlink:label="loc_us-gaapOtherCostAndExpenseOperating" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapOtherCostAndExpenseOperating" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="loc_us-gaapLaborAndRelatedExpense" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapLaborAndRelatedExpense" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfessionalFees" xlink:label="loc_us-gaapProfessionalFees" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapProfessionalFees" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GeneralAndAdministrativeExpense" xlink:label="loc_us-gaapGeneralAndAdministrativeExpense" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapGeneralAndAdministrativeExpense" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_FacilitiesCosts" xlink:label="loc_OPTTFacilitiesCosts" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_OPTTFacilitiesCosts" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaapShareBasedCompensation" />
      <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapShareBasedCompensation" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationAndAmortization" xlink:label="loc_us-gaapDepreciationAndAmortization" />
      <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapDepreciationAndAmortization" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherOperatingIncomeExpenseNet" xlink:label="loc_us-gaapOtherOperatingIncomeExpenseNet" />
      <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapOtherOperatingIncomeExpenseNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNet" xlink:label="loc_us-gaapInterestIncomeExpenseNet" />
      <link:calculationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapInterestIncomeExpenseNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProvisionForDoubtfulAccounts" xlink:label="loc_us-gaapProvisionForDoubtfulAccounts" />
      <link:calculationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapProvisionForDoubtfulAccounts" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="optt-20260131.xsd#OPTT_ChangeInFairValueOfDerivative" xlink:label="loc_OPTTChangeInFairValueOfDerivative" />
      <link:calculationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_OPTTChangeInFairValueOfDerivative" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt" xlink:label="loc_us-gaapGainsLossesOnExtinguishmentOfDebt" />
      <link:calculationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetIncomeLoss" xlink:to="loc_us-gaapGainsLossesOnExtinguishmentOfDebt" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://oceanpowertechnologies.com/role/OperatingSegmentsAndGeographicInformationDetailsNarrative" xlink:title="999064 - Disclosure - Operating Segments and Geographic Information (Details Narrative)" />
</link:linkbase>
