<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:ca2b7fcf-87dc-46e3-bfbc-0c0d8846cd39,g:5c0b25c7-5ace-45cc-b445-3ee05bf210ff-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.billiontoone.com/role/BalanceSheets" xlink:type="simple" xlink:href="blln-20250930.xsd#BalanceSheets"/>
  <link:calculationLink xlink:role="http://www.billiontoone.com/role/BalanceSheets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_b9d78c09-4897-4c92-9917-657829966bdd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_81651a3e-ef13-41e7-b255-609fa9bc8864" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_b9d78c09-4897-4c92-9917-657829966bdd" xlink:to="loc_us-gaap_CommonStockValue_81651a3e-ef13-41e7-b255-609fa9bc8864" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapital_dc6c52dd-06c1-4b55-8449-3ceeb1527028" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapital"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_b9d78c09-4897-4c92-9917-657829966bdd" xlink:to="loc_us-gaap_AdditionalPaidInCapital_dc6c52dd-06c1-4b55-8449-3ceeb1527028" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_92a16d83-81e1-4fbb-af06-bbcdbf20b4d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_StockholdersEquity_b9d78c09-4897-4c92-9917-657829966bdd" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_92a16d83-81e1-4fbb-af06-bbcdbf20b4d7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_4ff19e49-9b63-46b4-bb6d-33eb9a75dc5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:to="loc_us-gaap_AccountsPayableCurrent_4ff19e49-9b63-46b4-bb6d-33eb9a75dc5e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccountsPayableAndAccruedLiabilities_87af5c21-39c6-445e-9b8a-01e0f9586793" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAccountsPayableAndAccruedLiabilities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:to="loc_us-gaap_OtherAccountsPayableAndAccruedLiabilities_87af5c21-39c6-445e-9b8a-01e0f9586793" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedSalesCommissionCurrent_0d7892d7-fc73-4bab-9165-6540cf5fdd0f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedSalesCommissionCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:to="loc_us-gaap_AccruedSalesCommissionCurrent_0d7892d7-fc73-4bab-9165-6540cf5fdd0f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedEmployeeBenefitsCurrent_db6e4f94-4922-4a02-a328-3798d983dd2e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedEmployeeBenefitsCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:to="loc_us-gaap_AccruedEmployeeBenefitsCurrent_db6e4f94-4922-4a02-a328-3798d983dd2e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_4b26fe86-27dd-4cca-9a24-9412fb88953a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_4b26fe86-27dd-4cca-9a24-9412fb88953a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_f5f92191-3b8c-43e9-a725-6ba3674e0690" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_f5f92191-3b8c-43e9-a725-6ba3674e0690" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityCurrent_d0696ff3-73a7-47c4-a1e5-69a0e3f59f20" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityCurrent"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesCurrent_0cb99a48-f7e1-447e-bbb5-32ad2c02c3b6" xlink:to="loc_us-gaap_FinanceLeaseLiabilityCurrent_d0696ff3-73a7-47c4-a1e5-69a0e3f59f20" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_416ae2f2-0c14-4bba-9ac0-403dbf3951b7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_8c5e842b-e9fa-4ae7-a468-56fad9abc9af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_416ae2f2-0c14-4bba-9ac0-403dbf3951b7" xlink:to="loc_us-gaap_LiabilitiesCurrent_8c5e842b-e9fa-4ae7-a468-56fad9abc9af" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_850e5286-415f-417e-b05b-5283e72fa4f5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_416ae2f2-0c14-4bba-9ac0-403dbf3951b7" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_850e5286-415f-417e-b05b-5283e72fa4f5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_24225e6d-9355-4a26-bacf-bfa368cf074e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseLiabilityNoncurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_416ae2f2-0c14-4bba-9ac0-403dbf3951b7" xlink:to="loc_us-gaap_FinanceLeaseLiabilityNoncurrent_24225e6d-9355-4a26-bacf-bfa368cf074e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_b8b5bdaf-f0ff-4a0c-8581-8df10fb82c5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebt"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_416ae2f2-0c14-4bba-9ac0-403dbf3951b7" xlink:to="loc_us-gaap_LongTermDebt_b8b5bdaf-f0ff-4a0c-8581-8df10fb82c5a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesNoncurrent_464a8987-750a-4ceb-be2a-2d7368061e9a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherLiabilitiesNoncurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Liabilities_416ae2f2-0c14-4bba-9ac0-403dbf3951b7" xlink:to="loc_us-gaap_OtherLiabilitiesNoncurrent_464a8987-750a-4ceb-be2a-2d7368061e9a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_6f14b3fb-35fe-4705-996a-21fa025db46d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_161276b0-a296-4083-a8b4-fa17859f6c0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Liabilities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_6f14b3fb-35fe-4705-996a-21fa025db46d" xlink:to="loc_us-gaap_Liabilities_161276b0-a296-4083-a8b4-fa17859f6c0b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingencies_61544940-2e01-4784-836b-83d72f46ba0b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommitmentsAndContingencies"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_6f14b3fb-35fe-4705-996a-21fa025db46d" xlink:to="loc_us-gaap_CommitmentsAndContingencies_61544940-2e01-4784-836b-83d72f46ba0b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_f18987ba-c946-4465-8520-eed69691abfb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TemporaryEquityCarryingAmountAttributableToParent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_6f14b3fb-35fe-4705-996a-21fa025db46d" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountAttributableToParent_f18987ba-c946-4465-8520-eed69691abfb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_c4be2481-b81b-44aa-a2da-360ef4db5232" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquity"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity_6f14b3fb-35fe-4705-996a-21fa025db46d" xlink:to="loc_us-gaap_StockholdersEquity_c4be2481-b81b-44aa-a2da-360ef4db5232" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_93c25bfd-d6bf-40eb-acac-812c2c865081" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_a3edc906-2145-4dc6-841e-08ff60f7ea33" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_93c25bfd-d6bf-40eb-acac-812c2c865081" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_a3edc906-2145-4dc6-841e-08ff60f7ea33" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_2268345c-2150-46dd-aea0-ff3efdc96b74" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_93c25bfd-d6bf-40eb-acac-812c2c865081" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_2268345c-2150-46dd-aea0-ff3efdc96b74" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryNet_5a757be7-7fa7-44a4-ae40-8aaa138b10d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryNet"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_93c25bfd-d6bf-40eb-acac-812c2c865081" xlink:to="loc_us-gaap_InventoryNet_5a757be7-7fa7-44a4-ae40-8aaa138b10d9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_ca98607c-b8b4-47db-a7ca-abf2543ef478" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsCurrent_93c25bfd-d6bf-40eb-acac-812c2c865081" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_ca98607c-b8b4-47db-a7ca-abf2543ef478" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_5439c77c-942d-423d-9d80-120add8b2596" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Assets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_307466ef-d530-4150-8cf4-49742f9c9871" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_5439c77c-942d-423d-9d80-120add8b2596" xlink:to="loc_us-gaap_AssetsCurrent_307466ef-d530-4150-8cf4-49742f9c9871" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_483c6aa2-a2d6-4fda-a39b-3fcaa03b9345" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_5439c77c-942d-423d-9d80-120add8b2596" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_483c6aa2-a2d6-4fda-a39b-3fcaa03b9345" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_33ee22f6-27bb-4abe-9649-2737ba5fb64e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_5439c77c-942d-423d-9d80-120add8b2596" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_33ee22f6-27bb-4abe-9649-2737ba5fb64e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_e6758dd8-4b02-4bf2-a674-f41118e4e2ef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_Assets_5439c77c-942d-423d-9d80-120add8b2596" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_e6758dd8-4b02-4bf2-a674-f41118e4e2ef" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.billiontoone.com/role/StatementsofOperationsandComprehensiveIncomeLoss" xlink:type="simple" xlink:href="blln-20250930.xsd#StatementsofOperationsandComprehensiveIncomeLoss"/>
  <link:calculationLink xlink:role="http://www.billiontoone.com/role/StatementsofOperationsandComprehensiveIncomeLoss" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_b05e9934-7b57-4fe0-b083-f416e88e0366" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_0818d363-ccea-427f-8f07-1899438b17a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GrossProfit"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_b05e9934-7b57-4fe0-b083-f416e88e0366" xlink:to="loc_us-gaap_GrossProfit_0818d363-ccea-427f-8f07-1899438b17a9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_636dadf4-d703-4ab4-9f0c-d76c53e71f39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingIncomeLoss_b05e9934-7b57-4fe0-b083-f416e88e0366" xlink:to="loc_us-gaap_OperatingExpenses_636dadf4-d703-4ab4-9f0c-d76c53e71f39" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_6c26d784-e6e9-46ff-a4df-f43728e3873f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_8d7b77fa-1067-4574-be33-70307f60ec98" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_6c26d784-e6e9-46ff-a4df-f43728e3873f" xlink:to="loc_us-gaap_OperatingIncomeLoss_8d7b77fa-1067-4574-be33-70307f60ec98" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_f8b0f59d-ca93-42e6-a234-6b117f008b77" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_6c26d784-e6e9-46ff-a4df-f43728e3873f" xlink:to="loc_us-gaap_NonoperatingIncomeExpense_f8b0f59d-ca93-42e6-a234-6b117f008b77" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_f29a2898-253f-4674-8714-6ea7e91fc0a2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_a1e85ce8-8a28-4da6-ab3e-98b4d12f0c2b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_f29a2898-253f-4674-8714-6ea7e91fc0a2" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_a1e85ce8-8a28-4da6-ab3e-98b4d12f0c2b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpense_4721bbbe-7602-4821-a8df-18e31bd6b797" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SellingGeneralAndAdministrativeExpense"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_OperatingExpenses_f29a2898-253f-4674-8714-6ea7e91fc0a2" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpense_4721bbbe-7602-4821-a8df-18e31bd6b797" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_fd84117d-f538-4a66-b482-c8bcb9b39669" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_2ca22418-0cb2-4f6a-ba5f-9cd8ee5f8b41" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_fd84117d-f538-4a66-b482-c8bcb9b39669" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_2ca22418-0cb2-4f6a-ba5f-9cd8ee5f8b41" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_a74393bd-f9dd-4f34-927b-da81e6167d19" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLoss_fd84117d-f538-4a66-b482-c8bcb9b39669" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_a74393bd-f9dd-4f34-927b-da81e6167d19" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019b03fc-e759-73d9-942a-bb5db0fdb665" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019b03fc-e759-7033-bbb8-172f1ee134b6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_019b03fc-e759-73d9-942a-bb5db0fdb665" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019b03fc-e759-7033-bbb8-172f1ee134b6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_8c14e116-a88c-4fc8-9521-dddbb62d34d2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GrossProfit"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_5d0e99a5-fccf-44bd-a3fe-ae65d085ec82" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_8c14e116-a88c-4fc8-9521-dddbb62d34d2" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_5d0e99a5-fccf-44bd-a3fe-ae65d085ec82" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_4dc74998-355b-48cd-8fcb-40746328bed9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_GrossProfit_8c14e116-a88c-4fc8-9521-dddbb62d34d2" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_4dc74998-355b-48cd-8fcb-40746328bed9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_fee32d64-3f0c-4592-8b24-5b2b7652d4b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_37407dd0-6154-41a6-8899-f6783f5f4e77" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTax_fee32d64-3f0c-4592-8b24-5b2b7652d4b5" xlink:to="loc_us-gaap_NetIncomeLoss_37407dd0-6154-41a6-8899-f6783f5f4e77" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_c6b43a11-61cb-4e07-abe2-f665ae866078" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_29c0f0de-9d2c-462e-9a74-a98ad6849b0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_c6b43a11-61cb-4e07-abe2-f665ae866078" xlink:to="loc_us-gaap_NetIncomeLoss_29c0f0de-9d2c-462e-9a74-a98ad6849b0a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_02e3ee2e-61e2-4b12-8c23-9b1f4529bab3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_c6b43a11-61cb-4e07-abe2-f665ae866078" xlink:to="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossBasic_02e3ee2e-61e2-4b12-8c23-9b1f4529bab3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NonoperatingIncomeExpense_560cb030-ba1f-497b-8f76-fad31bb6e920" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NonoperatingIncomeExpense"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_80a521ce-5e47-48b5-a965-07a04faf0d61" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_560cb030-ba1f-497b-8f76-fad31bb6e920" xlink:to="loc_us-gaap_InvestmentIncomeInterest_80a521ce-5e47-48b5-a965-07a04faf0d61" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_37c1510d-dc28-43e4-8d6e-b18ec54ec718" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_560cb030-ba1f-497b-8f76-fad31bb6e920" xlink:to="loc_us-gaap_InterestExpenseNonoperating_37c1510d-dc28-43e4-8d6e-b18ec54ec718" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_4ad49011-2caf-4eca-af7e-4cde1c5fe82e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_560cb030-ba1f-497b-8f76-fad31bb6e920" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_4ad49011-2caf-4eca-af7e-4cde1c5fe82e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_FairValueAdjustmentOfTermLoanIncludingInterest_34208d4f-7684-4d6a-80f5-ab8f1c6c24d7" xlink:href="blln-20250930.xsd#blln_FairValueAdjustmentOfTermLoanIncludingInterest"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_560cb030-ba1f-497b-8f76-fad31bb6e920" xlink:to="loc_blln_FairValueAdjustmentOfTermLoanIncludingInterest_34208d4f-7684-4d6a-80f5-ab8f1c6c24d7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_FairValueAdjustmentOfConvertibleNotes_d4680216-1206-48af-9948-adeb0d1139ae" xlink:href="blln-20250930.xsd#blln_FairValueAdjustmentOfConvertibleNotes"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_560cb030-ba1f-497b-8f76-fad31bb6e920" xlink:to="loc_blln_FairValueAdjustmentOfConvertibleNotes_d4680216-1206-48af-9948-adeb0d1139ae" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_3a57a98e-e865-47b8-b5b4-420bc52258dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NonoperatingIncomeExpense_560cb030-ba1f-497b-8f76-fad31bb6e920" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_3a57a98e-e865-47b8-b5b4-420bc52258dd" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.billiontoone.com/role/StatementsofCashFlows" xlink:type="simple" xlink:href="blln-20250930.xsd#StatementsofCashFlows"/>
  <link:calculationLink xlink:role="http://www.billiontoone.com/role/StatementsofCashFlows" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_e0aa23d8-439e-4172-aa54-959957473a15" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_e0aa23d8-439e-4172-aa54-959957473a15" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfDebt_d3d9ceb2-3f80-4608-9de4-fc22303e3120" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfDebt"/>
    <link:calculationArc order="2" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_RepaymentsOfDebt_d3d9ceb2-3f80-4608-9de4-fc22303e3120" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_2dfdfa43-f805-4c30-b20c-965e0fdb34d3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts"/>
    <link:calculationArc order="3" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_2dfdfa43-f805-4c30-b20c-965e0fdb34d3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeasePrincipalPayments_d0fc8aba-7439-48dd-80b3-136340b6ca3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeasePrincipalPayments"/>
    <link:calculationArc order="4" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_FinanceLeasePrincipalPayments_d0fc8aba-7439-48dd-80b3-136340b6ca3d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_48aae67b-6af3-44b8-89d7-6124758950c3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock"/>
    <link:calculationArc order="5" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_PaymentsForRepurchaseOfCommonStock_48aae67b-6af3-44b8-89d7-6124758950c3" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_df376d30-fe8c-4d7e-8e74-08a7e2121502" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsOfDebtIssuanceCosts"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_df376d30-fe8c-4d7e-8e74-08a7e2121502" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_PaymentsOfDeferredOfferingCosts_ae6fb669-c794-4bb8-9cb3-1a12a9a24e27" xlink:href="blln-20250930.xsd#blln_PaymentsOfDeferredOfferingCosts"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_blln_PaymentsOfDeferredOfferingCosts_ae6fb669-c794-4bb8-9cb3-1a12a9a24e27" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_6a459df2-a852-4e1e-b4e1-eea689754105" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromStockOptionsExercised"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_6a459df2-a852-4e1e-b4e1-eea689754105" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock_22796974-5beb-4c74-80a6-bed5586107fd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_37dc4ad1-91f8-4f58-b4cc-c29e02e8dc89" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock_22796974-5beb-4c74-80a6-bed5586107fd" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_991cac06-ff93-4306-a0ba-57f039470b3d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_a8ea53fc-c2ab-4b4a-a57c-72700b13e1a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:calculationArc order="1" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_991cac06-ff93-4306-a0ba-57f039470b3d" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_a8ea53fc-c2ab-4b4a-a57c-72700b13e1a5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_6ccd2b52-480c-459e-9384-758306bb9fa8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetIncomeLoss"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_NetIncomeLoss_6ccd2b52-480c-459e-9384-758306bb9fa8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_13968121-22f7-40bf-a9dd-537571b30d34" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensation"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_ShareBasedCompensation_13968121-22f7-40bf-a9dd-537571b30d34" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_9ddd1e58-adcc-4c60-8bf5-166d16fa7626" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_DepreciationAndAmortization_9ddd1e58-adcc-4c60-8bf5-166d16fa7626" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfFinancingCosts_e4a3f8d2-0130-4ea1-bd6e-243d8e19b8e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfFinancingCosts"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_AmortizationOfFinancingCosts_e4a3f8d2-0130-4ea1-bd6e-243d8e19b8e4" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense_def09947-4856-48d2-9b23-15194fb67a9e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense_def09947-4856-48d2-9b23-15194fb67a9e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_c68de875-b267-4b3e-9ea7-4b5e6f2527f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:calculationArc order="6" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_c68de875-b267-4b3e-9ea7-4b5e6f2527f6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_FairValueAdjustmentOfCommonStockWarrantLiability_612f2742-fc59-44e9-b007-0daecbfb5849" xlink:href="blln-20250930.xsd#blln_FairValueAdjustmentOfCommonStockWarrantLiability"/>
    <link:calculationArc order="7" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_blln_FairValueAdjustmentOfCommonStockWarrantLiability_612f2742-fc59-44e9-b007-0daecbfb5849" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_FairValueAdjustmentOfRedeemableConvertiblePreferredStockWarrantLiability_ed2b79fd-140f-4e04-98c0-f7f020ecabbb" xlink:href="blln-20250930.xsd#blln_FairValueAdjustmentOfRedeemableConvertiblePreferredStockWarrantLiability"/>
    <link:calculationArc order="8" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_blln_FairValueAdjustmentOfRedeemableConvertiblePreferredStockWarrantLiability_ed2b79fd-140f-4e04-98c0-f7f020ecabbb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_3d35b407-c356-4208-b8af-7a6d191d91f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:calculationArc order="9" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_3d35b407-c356-4208-b8af-7a6d191d91f6" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_FairValueAdjustmentOfTermLoan_3aa7b920-ea94-451c-b03c-785fc08ae91b" xlink:href="blln-20250930.xsd#blln_FairValueAdjustmentOfTermLoan"/>
    <link:calculationArc order="10" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_blln_FairValueAdjustmentOfTermLoan_3aa7b920-ea94-451c-b03c-785fc08ae91b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_FairValueAdjustmentOfConvertibleNotes_2210e65c-b4bc-4775-90f7-deeba4e486f7" xlink:href="blln-20250930.xsd#blln_FairValueAdjustmentOfConvertibleNotes"/>
    <link:calculationArc order="11" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_blln_FairValueAdjustmentOfConvertibleNotes_2210e65c-b4bc-4775-90f7-deeba4e486f7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_be551c13-9e1d-4e6a-8c9b-309aafc7957f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:calculationArc order="12" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_be551c13-9e1d-4e6a-8c9b-309aafc7957f" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInInventories_c502192f-6459-4b30-9e5e-daa1f128dee1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInInventories"/>
    <link:calculationArc order="13" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInInventories_c502192f-6459-4b30-9e5e-daa1f128dee1" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_b0c5fb94-4b8b-4a5e-a523-3d9d66e8f961" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:calculationArc order="14" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_b0c5fb94-4b8b-4a5e-a523-3d9d66e8f961" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_f6a96fd8-6f07-4ac6-8c6e-d23f891a7a8c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentAssets"/>
    <link:calculationArc order="15" weight="-1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_f6a96fd8-6f07-4ac6-8c6e-d23f891a7a8c" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_84a8b062-cd1e-4703-8c1f-58e5e82d74d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:calculationArc order="16" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_84a8b062-cd1e-4703-8c1f-58e5e82d74d9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities_b1fda93a-a8c1-4681-bf98-baac387eb98d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities"/>
    <link:calculationArc order="17" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherAccountsPayableAndAccruedLiabilities_b1fda93a-a8c1-4681-bf98-baac387eb98d" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_1f3b6304-e57c-4e97-988c-ee616730a742" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <link:calculationArc order="18" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_1f3b6304-e57c-4e97-988c-ee616730a742" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_ef175ba3-d4f7-422a-a468-309313679646" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities"/>
    <link:calculationArc order="19" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInEmployeeRelatedLiabilities_ef175ba3-d4f7-422a-a468-309313679646" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_05a4105e-5c44-4746-8ae1-07105943c5b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInContractWithCustomerLiability"/>
    <link:calculationArc order="20" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInContractWithCustomerLiability_05a4105e-5c44-4746-8ae1-07105943c5b5" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_694a2225-9739-41da-aa8b-57acbd0d946b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability"/>
    <link:calculationArc order="21" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_694a2225-9739-41da-aa8b-57acbd0d946b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_DebtIssuanceCostsExpensedUponElectionOfFairValueOption_8f33b7ec-607f-4ae8-9bce-799a290cb1fc" xlink:href="blln-20250930.xsd#blln_DebtIssuanceCostsExpensedUponElectionOfFairValueOption"/>
    <link:calculationArc order="22" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_31a23afb-fa11-4df4-8d58-b163e5afd6a7" xlink:to="loc_blln_DebtIssuanceCostsExpensedUponElectionOfFairValueOption_8f33b7ec-607f-4ae8-9bce-799a290cb1fc" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_68ac5455-62cd-4d00-b083-3d905c98d9dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3d17f05c-3462-4f64-a536-0c2d6ab5969a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_68ac5455-62cd-4d00-b083-3d905c98d9dc" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_3d17f05c-3462-4f64-a536-0c2d6ab5969a" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_a66d106a-1c14-4143-9f44-eb1c7be52d26" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_68ac5455-62cd-4d00-b083-3d905c98d9dc" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_a66d106a-1c14-4143-9f44-eb1c7be52d26" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_3101a6ea-a0e4-4716-8f1c-6fe3273f0063" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_68ac5455-62cd-4d00-b083-3d905c98d9dc" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_3101a6ea-a0e4-4716-8f1c-6fe3273f0063" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.billiontoone.com/role/FairValueMeasurementsSummaryofFairValueMeasurementofAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="blln-20250930.xsd#FairValueMeasurementsSummaryofFairValueMeasurementofAssetsandLiabilitiesDetails"/>
  <link:calculationLink xlink:role="http://www.billiontoone.com/role/FairValueMeasurementsSummaryofFairValueMeasurementofAssetsandLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_fc63fc16-9648-4d29-94dc-9cf918f40898" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_d1136137-fec1-4e3e-b0e9-419b2cdf7868" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CashAndCashEquivalentsFairValueDisclosure"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AssetsFairValueDisclosure_fc63fc16-9648-4d29-94dc-9cf918f40898" xlink:to="loc_us-gaap_CashAndCashEquivalentsFairValueDisclosure_d1136137-fec1-4e3e-b0e9-419b2cdf7868" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_5aef8146-8f2a-4d57-956a-4c8bf0c79fc5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesFairValueDisclosure"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_WarrantsFairValueDisclosure_d4a69184-d52b-45f6-a131-22db4080f0a7" xlink:href="blln-20250930.xsd#blln_WarrantsFairValueDisclosure"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosure_5aef8146-8f2a-4d57-956a-4c8bf0c79fc5" xlink:to="loc_blln_WarrantsFairValueDisclosure_d4a69184-d52b-45f6-a131-22db4080f0a7" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LoansPayableFairValueDisclosure_95452410-0e6a-4fa4-8a2d-9f2a3475d814" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LoansPayableFairValueDisclosure"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosure_5aef8146-8f2a-4d57-956a-4c8bf0c79fc5" xlink:to="loc_us-gaap_LoansPayableFairValueDisclosure_95452410-0e6a-4fa4-8a2d-9f2a3475d814" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.billiontoone.com/role/AccruedExpensesandOtherCurrentLiabilitiesDetails" xlink:type="simple" xlink:href="blln-20250930.xsd#AccruedExpensesandOtherCurrentLiabilitiesDetails"/>
  <link:calculationLink xlink:role="http://www.billiontoone.com/role/AccruedExpensesandOtherCurrentLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedProfessionalFeesCurrent_6fe7dafc-51e5-494a-a277-773264d01b7e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedProfessionalFeesCurrent"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_us-gaap_AccruedProfessionalFeesCurrent_6fe7dafc-51e5-494a-a277-773264d01b7e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_AccruedInventoryCurrent_f819c139-6abd-4142-93d4-600d8f4330cb" xlink:href="blln-20250930.xsd#blln_AccruedInventoryCurrent"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_blln_AccruedInventoryCurrent_f819c139-6abd-4142-93d4-600d8f4330cb" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_AccruedFixedAssetPurchasesCurrent_681d67c8-abb6-4347-bfcb-1340412c02f8" xlink:href="blln-20250930.xsd#blln_AccruedFixedAssetPurchasesCurrent"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_blln_AccruedFixedAssetPurchasesCurrent_681d67c8-abb6-4347-bfcb-1340412c02f8" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_AccruedInsurancePayorLiabilityCurrent_3aa1c427-555f-4837-8792-8de5043d5658" xlink:href="blln-20250930.xsd#blln_AccruedInsurancePayorLiabilityCurrent"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_blln_AccruedInsurancePayorLiabilityCurrent_3aa1c427-555f-4837-8792-8de5043d5658" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxesPayableCurrent_b433c17e-aa00-4bdc-8c7d-722859e77d00" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TaxesPayableCurrent"/>
    <link:calculationArc order="5" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_us-gaap_TaxesPayableCurrent_b433c17e-aa00-4bdc-8c7d-722859e77d00" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_AccruedInformationTechnologyPurchasesCurrent_4a07d066-84f3-4cfa-bc81-8f515371e42e" xlink:href="blln-20250930.xsd#blln_AccruedInformationTechnologyPurchasesCurrent"/>
    <link:calculationArc order="6" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_blln_AccruedInformationTechnologyPurchasesCurrent_4a07d066-84f3-4cfa-bc81-8f515371e42e" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_AccruedLegalExpensesCurrent_ef0a71f4-2d8d-41ac-a88c-6c1cdc8e961b" xlink:href="blln-20250930.xsd#blln_AccruedLegalExpensesCurrent"/>
    <link:calculationArc order="7" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_blln_AccruedLegalExpensesCurrent_ef0a71f4-2d8d-41ac-a88c-6c1cdc8e961b" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_AccruedPhlebotomyExpensesCurrent_a73bdd98-610e-4aa5-ad29-8b8d71364350" xlink:href="blln-20250930.xsd#blln_AccruedPhlebotomyExpensesCurrent"/>
    <link:calculationArc order="8" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_blln_AccruedPhlebotomyExpensesCurrent_a73bdd98-610e-4aa5-ad29-8b8d71364350" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedInsuranceCurrent_17b41e11-0d00-4e27-aa2d-1becd2ba23a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedInsuranceCurrent"/>
    <link:calculationArc order="9" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_us-gaap_AccruedInsuranceCurrent_17b41e11-0d00-4e27-aa2d-1becd2ba23a9" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedRentCurrent_3ecd52f9-d747-4374-b3c6-738efe9c3a20" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedRentCurrent"/>
    <link:calculationArc order="10" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_us-gaap_AccruedRentCurrent_3ecd52f9-d747-4374-b3c6-738efe9c3a20" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_blln_AccruedClinicalExpensesCurrent_6817d14e-eea0-45a0-869d-99c766f7ceea" xlink:href="blln-20250930.xsd#blln_AccruedClinicalExpensesCurrent"/>
    <link:calculationArc order="11" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_blln_AccruedClinicalExpensesCurrent_6817d14e-eea0-45a0-869d-99c766f7ceea" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAccruedLiabilitiesCurrent_c3a1e50d-b2b9-443e-ac57-1386fee66189" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAccruedLiabilitiesCurrent"/>
    <link:calculationArc order="12" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_910350d7-6773-4f57-90d7-b2a55bbe3865" xlink:to="loc_us-gaap_OtherAccruedLiabilitiesCurrent_c3a1e50d-b2b9-443e-ac57-1386fee66189" xlink:type="arc"/>
  </link:calculationLink>
  <link:roleRef roleURI="http://www.billiontoone.com/role/NetIncomeLossPerShareAttributabletoShareholdersComputationofBasicandDilutiveNetLossPerShareDetails" xlink:type="simple" xlink:href="blln-20250930.xsd#NetIncomeLossPerShareAttributabletoShareholdersComputationofBasicandDilutiveNetLossPerShareDetails"/>
  <link:calculationLink xlink:role="http://www.billiontoone.com/role/NetIncomeLossPerShareAttributabletoShareholdersComputationofBasicandDilutiveNetLossPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_6b8b5e99-ac64-4b30-b96f-fe76a70266c0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_6b9ab442-25ef-4729-9f00-42b5745cb0da" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:calculationArc order="1" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_6b8b5e99-ac64-4b30-b96f-fe76a70266c0" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_6b9ab442-25ef-4729-9f00-42b5745cb0da" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_dda1e83d-0aee-4da3-9481-ba776cc5c2b2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements"/>
    <link:calculationArc order="2" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_6b8b5e99-ac64-4b30-b96f-fe76a70266c0" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_dda1e83d-0aee-4da3-9481-ba776cc5c2b2" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_999cce3f-0982-4654-97c9-7bbdd1421e37" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants"/>
    <link:calculationArc order="3" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_6b8b5e99-ac64-4b30-b96f-fe76a70266c0" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToCallOptionsAndWarrants_999cce3f-0982-4654-97c9-7bbdd1421e37" xlink:type="arc"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_e2551c09-db08-4c94-a6bb-2566e485835f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities"/>
    <link:calculationArc order="4" weight="1.0" xlink:arcrole="http://www.xbrl.org/2003/arcrole/summation-item" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_6b8b5e99-ac64-4b30-b96f-fe76a70266c0" xlink:to="loc_us-gaap_IncrementalCommonSharesAttributableToConversionOfDebtSecurities_e2551c09-db08-4c94-a6bb-2566e485835f" xlink:type="arc"/>
  </link:calculationLink>
</link:linkbase>
