<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.5c -->
    <!-- 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="obai-20260630.xsd#Cover" roleURI="http://ourbond.com/role/Cover" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#BalanceSheets" roleURI="http://ourbond.com/role/BalanceSheets" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#BalanceSheetsParenthetical" roleURI="http://ourbond.com/role/BalanceSheetsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#StatementsOfOperations" roleURI="http://ourbond.com/role/StatementsOfOperations" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#StatementsOfComprehensiveLoss" roleURI="http://ourbond.com/role/StatementsOfComprehensiveLoss" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#StatementsOfStockholdersEquity" roleURI="http://ourbond.com/role/StatementsOfStockholdersEquity" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#StatementsOfCashFlows" roleURI="http://ourbond.com/role/StatementsOfCashFlows" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#SummaryOfSignificantAccountingPolicies" roleURI="http://ourbond.com/role/SummaryOfSignificantAccountingPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#Revenue" roleURI="http://ourbond.com/role/Revenue" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#SegmentAndGeographicalInformation" roleURI="http://ourbond.com/role/SegmentAndGeographicalInformation" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#EarningsPerShare" roleURI="http://ourbond.com/role/EarningsPerShare" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#BalanceSheetDetail" roleURI="http://ourbond.com/role/BalanceSheetDetail" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#LoanAndPromissoryNote" roleURI="http://ourbond.com/role/LoanAndPromissoryNote" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#RelatedParty" roleURI="http://ourbond.com/role/RelatedParty" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#PreferredStockAndCommonStock" roleURI="http://ourbond.com/role/PreferredStockAndCommonStock" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#Stock-basedCompensation" roleURI="http://ourbond.com/role/Stock-basedCompensation" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#IncomeTaxes" roleURI="http://ourbond.com/role/IncomeTaxes" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#CommitmentsAndContingencies" roleURI="http://ourbond.com/role/CommitmentsAndContingencies" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#SubsequentEvents" roleURI="http://ourbond.com/role/SubsequentEvents" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#SummaryOfSignificantAccountingPoliciesPolicies" roleURI="http://ourbond.com/role/SummaryOfSignificantAccountingPoliciesPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#RevenueTables" roleURI="http://ourbond.com/role/RevenueTables" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#SegmentAndGeographicalInformationTables" roleURI="http://ourbond.com/role/SegmentAndGeographicalInformationTables" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#EarningsPerShareTables" roleURI="http://ourbond.com/role/EarningsPerShareTables" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#BalanceSheetDetailTables" roleURI="http://ourbond.com/role/BalanceSheetDetailTables" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#PreferredStockAndCommonStockTables" roleURI="http://ourbond.com/role/PreferredStockAndCommonStockTables" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#Stock-basedCompensationTables" roleURI="http://ourbond.com/role/Stock-basedCompensationTables" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfDisaggregationOfRevenueDetails" roleURI="http://ourbond.com/role/ScheduleOfDisaggregationOfRevenueDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfDeferredRevenueDetails" roleURI="http://ourbond.com/role/ScheduleOfDeferredRevenueDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#RevenueDetailsNarrative" roleURI="http://ourbond.com/role/RevenueDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfRevenueByGeographicAreaDetails" roleURI="http://ourbond.com/role/ScheduleOfRevenueByGeographicAreaDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfPropertyAndEquipmentByGeographicAreaDetails" roleURI="http://ourbond.com/role/ScheduleOfPropertyAndEquipmentByGeographicAreaDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfEarningsPerShareBasicAndDilutedDetails" roleURI="http://ourbond.com/role/ScheduleOfEarningsPerShareBasicAndDilutedDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfAntidilutiveSecuritiesEarningsPerShareDetails" roleURI="http://ourbond.com/role/ScheduleOfAntidilutiveSecuritiesEarningsPerShareDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfPrepaidExpensesAndOtherCurrentAssetsDetails" roleURI="http://ourbond.com/role/ScheduleOfPrepaidExpensesAndOtherCurrentAssetsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfPropertyAndEquipmentNetDetails" roleURI="http://ourbond.com/role/ScheduleOfPropertyAndEquipmentNetDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfAccruedAndOtherCurrentLiabilitiesDetails" roleURI="http://ourbond.com/role/ScheduleOfAccruedAndOtherCurrentLiabilitiesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#BalanceSheetDetailDetailsNarrative" roleURI="http://ourbond.com/role/BalanceSheetDetailDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#LoanAndPromissoryNoteDetailsNarrative" roleURI="http://ourbond.com/role/LoanAndPromissoryNoteDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#RelatedPartyDetailsNarrative" roleURI="http://ourbond.com/role/RelatedPartyDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfCompositionOfStockCapitalDetails" roleURI="http://ourbond.com/role/ScheduleOfCompositionOfStockCapitalDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#PreferredStockAndCommonStockDetailsNarrative" roleURI="http://ourbond.com/role/PreferredStockAndCommonStockDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#Stock-basedCompensationDetailsNarrative" roleURI="http://ourbond.com/role/Stock-basedCompensationDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfStockOptionActivityDetails" roleURI="http://ourbond.com/role/ScheduleOfStockOptionActivityDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#ScheduleOfStockBasedCompensationExpensesDetails" roleURI="http://ourbond.com/role/ScheduleOfStockBasedCompensationExpensesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#IncomeTaxesDetailsNarrative" roleURI="http://ourbond.com/role/IncomeTaxesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="obai-20260630.xsd#CommitmentsAndContingenciesDetailsNarrative" roleURI="http://ourbond.com/role/CommitmentsAndContingenciesDetailsNarrative" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/Cover" xlink:title="00000001 - Document - Cover" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/BalanceSheets" xlink:title="00000002 - Statement - Condensed Consolidated Balance Sheets (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaapAssetsCurrent" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaapPrepaidExpenseAndOtherAssetsCurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAssetsCurrent" xlink:to="loc_us-gaapPrepaidExpenseAndOtherAssetsCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaapLiabilitiesCurrent" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerLiabilityCurrent" xlink:label="loc_us-gaapContractWithCustomerLiabilityCurrent" />
      <link:calculationArc order="2" 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/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLoansPayableCurrent" xlink:label="loc_us-gaapOtherLoansPayableCurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapOtherLoansPayableCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtCurrent" xlink:label="loc_us-gaapLongTermDebtCurrent" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapLongTermDebtCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:label="loc_us-gaapAccountsPayableAndOtherAccruedLiabilitiesCurrent" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesCurrent" xlink:to="loc_us-gaapAccountsPayableAndOtherAccruedLiabilitiesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent" xlink:label="loc_us-gaapLongTermDebtNoncurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilities" xlink:to="loc_us-gaapLongTermDebtNoncurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaapAdditionalPaidInCapital" />
      <link:calculationArc order="3" 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/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaapAccumulatedOtherComprehensiveIncomeLossNetOfTax" />
      <link:calculationArc order="4" 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/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.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:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent" xlink:label="loc_us-gaapTemporaryEquityCarryingAmountAttributableToParent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapLiabilitiesAndStockholdersEquity" xlink:to="loc_us-gaapTemporaryEquityCarryingAmountAttributableToParent" xlink:type="arc" weight="1" />
      <link:calculationArc order="4" 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://ourbond.com/role/BalanceSheetsParenthetical" xlink:title="00000003 - Statement - Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/StatementsOfOperations" xlink:title="00000004 - Statement - Condensed Consolidated Statements of Operations (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GrossProfit" xlink:label="loc_us-gaapGrossProfit" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax" xlink:label="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapGrossProfit" xlink:to="loc_us-gaapRevenueFromContractWithCustomerExcludingAssessedTax" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingExpenses" xlink:label="loc_us-gaapOperatingExpenses" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ResearchAndDevelopmentExpense" xlink:label="loc_us-gaapResearchAndDevelopmentExpense" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapResearchAndDevelopmentExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingGeneralAndAdministrativeExpense" xlink:label="loc_us-gaapSellingGeneralAndAdministrativeExpense" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapSellingGeneralAndAdministrativeExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SellingAndMarketingExpense" xlink:label="loc_us-gaapSellingAndMarketingExpense" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapOperatingExpenses" xlink:to="loc_us-gaapSellingAndMarketingExpense" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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: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/2026/elts/us-gaap-2026.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="obai-20260630.xsd#OBAI_FinancialIncomeExpensesNet" xlink:label="loc_OBAIFinancialIncomeExpensesNet" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_OBAIFinancialIncomeExpensesNet" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIncome" xlink:label="loc_us-gaapOtherIncome" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapIncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="loc_us-gaapOtherIncome" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.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://ourbond.com/role/StatementsOfComprehensiveLoss" xlink:title="00000005 - Statement - Condensed Consolidated Statements of Comprehensive Loss (Unaudited)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComprehensiveIncomeNetOfTax" xlink:label="loc_us-gaapComprehensiveIncomeNetOfTax" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapNetIncomeLoss" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapComprehensiveIncomeNetOfTax" xlink:to="loc_us-gaapOtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/StatementsOfStockholdersEquity" xlink:title="00000006 - Statement - Condensed Consolidated Statements of Stockholders&apos; Equity (Unaudited)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/StatementsOfCashFlows" xlink:title="00000007 - Statement - Condensed Consolidated Statements of Cash Flows">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaapShareBasedCompensation" />
      <link:calculationArc order="2" 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="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaapDepreciation" />
      <link:calculationArc order="3" 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="obai-20260630.xsd#OBAI_CommonStockIssuedForLegalAndOtherServices" xlink:label="loc_OBAICommonStockIssuedForLegalAndOtherServices" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_OBAICommonStockIssuedForLegalAndOtherServices" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_LossOnConversionOfDebt" xlink:label="loc_OBAILossOnConversionOfDebt" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_OBAILossOnConversionOfDebt" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaapIncreaseDecreaseInAccountsReceivable" />
      <link:calculationArc order="6" 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/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaapIncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccountsPayable" xlink:label="loc_us-gaapIncreaseDecreaseInAccountsPayable" />
      <link:calculationArc order="8" 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/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability" xlink:label="loc_us-gaapIncreaseDecreaseInContractWithCustomerLiability" />
      <link:calculationArc order="9" 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/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities" xlink:label="loc_us-gaapIncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities" />
      <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInOperatingActivities" xlink:to="loc_us-gaapIncreaseDecreaseInAccruedLiabilitiesAndOtherOperatingLiabilities" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInInvestingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfRelatedPartyDebt" xlink:label="loc_us-gaapRepaymentsOfRelatedPartyDebt" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapRepaymentsOfRelatedPartyDebt" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfCFOnePreferenceStock" xlink:label="loc_OBAIProceedsFromIssuanceOfCFOnePreferenceStock" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfCFOnePreferenceStock" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfCFOnePreferenceStockFundraisingFees" xlink:label="loc_OBAIProceedsFromIssuanceOfCFOnePreferenceStockFundraisingFees" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfCFOnePreferenceStockFundraisingFees" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfSeriesCPreferredStock" xlink:label="loc_OBAIProceedsFromIssuanceOfSeriesCPreferredStock" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfSeriesCPreferredStock" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfCPreferredStockFundraisingFees" xlink:label="loc_OBAIProceedsFromIssuanceOfCPreferredStockFundraisingFees" />
      <link:calculationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfCPreferredStockFundraisingFees" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfPreferenceStockDOne" xlink:label="loc_OBAIProceedsFromIssuanceOfPreferenceStockDOne" />
      <link:calculationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfPreferenceStockDOne" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfPreferenceStockIssuanceCostsDOne" xlink:label="loc_OBAIProceedsFromIssuanceOfPreferenceStockIssuanceCostsDOne" />
      <link:calculationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfPreferenceStockIssuanceCostsDOne" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromNotesPayable" xlink:label="loc_us-gaapProceedsFromNotesPayable" />
      <link:calculationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromNotesPayable" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfNotesPayable" xlink:label="loc_us-gaapRepaymentsOfNotesPayable" />
      <link:calculationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapRepaymentsOfNotesPayable" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfIssuanceOfCommonStockUnderEquityLineOfCredit" xlink:label="loc_OBAIProceedsFromIssuanceOfIssuanceOfCommonStockUnderEquityLineOfCredit" />
      <link:calculationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfIssuanceOfCommonStockUnderEquityLineOfCredit" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfIssuanceOfCommonStockUnderEquityLineOfCreditIssuanceCosts" xlink:label="loc_OBAIProceedsFromIssuanceOfIssuanceOfCommonStockUnderEquityLineOfCreditIssuanceCosts" />
      <link:calculationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfIssuanceOfCommonStockUnderEquityLineOfCreditIssuanceCosts" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfCommonWarrantsExerciseOfSeriesCOne" xlink:label="loc_OBAIProceedsFromIssuanceOfCommonWarrantsExerciseOfSeriesCOne" />
      <link:calculationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfCommonWarrantsExerciseOfSeriesCOne" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfCommonWarrantsIssuanceCostsExerciseOfSeriesCOne" xlink:label="loc_OBAIProceedsFromIssuanceOfCommonWarrantsIssuanceCostsExerciseOfSeriesCOne" />
      <link:calculationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfCommonWarrantsIssuanceCostsExerciseOfSeriesCOne" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfCommonWarrantsExerciseOfSeriesDOne" xlink:label="loc_OBAIProceedsFromIssuanceOfCommonWarrantsExerciseOfSeriesDOne" />
      <link:calculationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfCommonWarrantsExerciseOfSeriesDOne" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_ProceedsFromIssuanceOfCommonWarrantsIssuanceCostsExerciseOfSeriesDOne" xlink:label="loc_OBAIProceedsFromIssuanceOfCommonWarrantsIssuanceCostsExerciseOfSeriesDOne" />
      <link:calculationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIProceedsFromIssuanceOfCommonWarrantsIssuanceCostsExerciseOfSeriesDOne" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfWarrants" xlink:label="loc_us-gaapProceedsFromIssuanceOfWarrants" />
      <link:calculationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_us-gaapProceedsFromIssuanceOfWarrants" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_DirectListingCosts" xlink:label="loc_OBAIDirectListingCosts" />
      <link:calculationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIDirectListingCosts" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="obai-20260630.xsd#OBAI_RedemptionOfSeriesGConvertiblePreferredStock" xlink:label="loc_OBAIRedemptionOfSeriesGConvertiblePreferredStock" />
      <link:calculationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapNetCashProvidedByUsedInFinancingActivities" xlink:to="loc_OBAIRedemptionOfSeriesGConvertiblePreferredStock" xlink:type="arc" weight="-1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:label="loc_us-gaapEffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect" xlink:to="loc_us-gaapEffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/SummaryOfSignificantAccountingPolicies" xlink:title="999008 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/Revenue" xlink:title="999009 - Disclosure - Revenue" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/SegmentAndGeographicalInformation" xlink:title="999010 - Disclosure - Segment and Geographical Information" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/EarningsPerShare" xlink:title="999011 - Disclosure - Earnings Per Share" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/BalanceSheetDetail" xlink:title="999012 - Disclosure - Balance Sheet Detail" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/LoanAndPromissoryNote" xlink:title="999013 - Disclosure - Loan and Promissory Note" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/RelatedParty" xlink:title="999014 - Disclosure - Related Party" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/PreferredStockAndCommonStock" xlink:title="999015 - Disclosure - Preferred Stock and Common Stock" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/Stock-basedCompensation" xlink:title="999016 - Disclosure - Stock-Based Compensation" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/IncomeTaxes" xlink:title="999017 - Disclosure - Income Taxes" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/CommitmentsAndContingencies" xlink:title="999018 - Disclosure - Commitments and Contingencies" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/SubsequentEvents" xlink:title="999019 - Disclosure - Subsequent Events" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="999020 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/RevenueTables" xlink:title="999021 - Disclosure - Revenue (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/SegmentAndGeographicalInformationTables" xlink:title="999022 - Disclosure - Segment and Geographical Information (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/EarningsPerShareTables" xlink:title="999023 - Disclosure - Earnings Per Share (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/BalanceSheetDetailTables" xlink:title="999024 - Disclosure - Balance Sheet Detail (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/PreferredStockAndCommonStockTables" xlink:title="999025 - Disclosure - Preferred Stock and Common Stock (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/Stock-basedCompensationTables" xlink:title="999026 - Disclosure - Stock-Based Compensation (Tables)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfDisaggregationOfRevenueDetails" xlink:title="999027 - Disclosure - Schedule of Disaggregation of Revenue (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfDeferredRevenueDetails" xlink:title="999028 - Disclosure - Schedule of Deferred Revenue (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/RevenueDetailsNarrative" xlink:title="999029 - Disclosure - Revenue (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfRevenueByGeographicAreaDetails" xlink:title="999030 - Disclosure - Schedule of Revenue by Geographic Area (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfPropertyAndEquipmentByGeographicAreaDetails" xlink:title="999031 - Disclosure - Schedule of Property and Equipment by Geographic Area (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfEarningsPerShareBasicAndDilutedDetails" xlink:title="999032 - Disclosure - Schedule of Earnings Per Share Basic and Diluted (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfAntidilutiveSecuritiesEarningsPerShareDetails" xlink:title="999033 - Disclosure - Schedule of Antidilutive Securities Earnings Per Share (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfPrepaidExpensesAndOtherCurrentAssetsDetails" xlink:title="999034 - Disclosure - Schedule of Prepaid Expenses and Other Current Assets (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:label="loc_us-gaapPrepaidExpenseAndOtherAssetsCurrent" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseCurrent" xlink:label="loc_us-gaapPrepaidExpenseCurrent" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapPrepaidExpenseAndOtherAssetsCurrent" xlink:to="loc_us-gaapPrepaidExpenseCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssetsCurrent" xlink:label="loc_us-gaapOtherAssetsCurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapPrepaidExpenseAndOtherAssetsCurrent" xlink:to="loc_us-gaapOtherAssetsCurrent" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfPropertyAndEquipmentNetDetails" xlink:title="999035 - Disclosure - Schedule of Property and Equipment, Net (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.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/2026/elts/us-gaap-2026.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://ourbond.com/role/ScheduleOfAccruedAndOtherCurrentLiabilitiesDetails" xlink:title="999036 - Disclosure - Schedule of Accrued and Other Current Liabilities (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilities" xlink:label="loc_us-gaapAccruedLiabilitiesAndOtherLiabilities" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedEmployeeBenefitsCurrent" xlink:label="loc_us-gaapAccruedEmployeeBenefitsCurrent" />
      <link:calculationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesAndOtherLiabilities" xlink:to="loc_us-gaapAccruedEmployeeBenefitsCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccruedLiabilitiesCurrent" xlink:label="loc_us-gaapAccruedLiabilitiesCurrent" />
      <link:calculationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesAndOtherLiabilities" xlink:to="loc_us-gaapAccruedLiabilitiesCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsPayableCurrent" xlink:label="loc_us-gaapDividendsPayableCurrent" />
      <link:calculationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesAndOtherLiabilities" xlink:to="loc_us-gaapDividendsPayableCurrent" xlink:type="arc" weight="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilitiesCurrent" xlink:label="loc_us-gaapOtherLiabilitiesCurrent" />
      <link:calculationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaapAccruedLiabilitiesAndOtherLiabilities" xlink:to="loc_us-gaapOtherLiabilitiesCurrent" xlink:type="arc" weight="1" />
    </link:calculationLink>
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/BalanceSheetDetailDetailsNarrative" xlink:title="999037 - Disclosure - Balance Sheet Detail (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/LoanAndPromissoryNoteDetailsNarrative" xlink:title="999038 - Disclosure - Loan and Promissory Note (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/RelatedPartyDetailsNarrative" xlink:title="999039 - Disclosure - Related Party (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfCompositionOfStockCapitalDetails" xlink:title="999040 - Disclosure - Schedule of Composition of Stock Capital (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/PreferredStockAndCommonStockDetailsNarrative" xlink:title="999041 - Disclosure - Preferred Stock and Common Stock (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/Stock-basedCompensationDetailsNarrative" xlink:title="999042 - Disclosure - Stock-Based Compensation (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfStockOptionActivityDetails" xlink:title="999043 - Disclosure - Schedule of Stock Option Activity (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/ScheduleOfStockBasedCompensationExpensesDetails" xlink:title="999044 - Disclosure - Schedule of Stock Based Compensation Expenses (Details)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/IncomeTaxesDetailsNarrative" xlink:title="999045 - Disclosure - Income Taxes (Details Narrative)" />
    <link:calculationLink xlink:type="extended" xlink:role="http://ourbond.com/role/CommitmentsAndContingenciesDetailsNarrative" xlink:title="999046 - Disclosure - Commitments and Contingencies (Details Narrative)" />
</link:linkbase>
