diff --git a/.changeset/chatty-taxes-hammer.md b/.changeset/chatty-taxes-hammer.md
new file mode 100644
index 0000000..64fea79
--- /dev/null
+++ b/.changeset/chatty-taxes-hammer.md
@@ -0,0 +1,5 @@
+---
+'@epilot/pricing': patch
+---
+
+Fix computeCumulativeValue to handle tax computation correctly
diff --git a/src/tiers/compute-cumulative-value.test.ts b/src/tiers/compute-cumulative-value.test.ts
index 3b83a68..fb7f684 100644
--- a/src/tiers/compute-cumulative-value.test.ts
+++ b/src/tiers/compute-cumulative-value.test.ts
@@ -57,11 +57,11 @@ describe('computeCumulativeValue', () => {
     tiers                  | quantityToSelectTier | unit        | locale       | currency | isTaxInclusive | showOnRequest | showStartsAt | tax             | expected
     ${baseTiersUnitAmount} | ${1}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${true}        | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '10,00\xa0€', totalWithPrecision: '10,00\xa0€', average: '10,00\xa0€/kWh', subtotal: '8,40\xa0€', subtotalWithPrecision: '8,403361344538\xa0€', subAverage: '8,40\xa0€/kWh', breakdown: [{ quantityUsed: '1 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '10,00\xa0€' }] }}
     ${baseTiersUnitAmount} | ${1}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${undefined}   | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '10,00\xa0€', totalWithPrecision: '10,00\xa0€', average: '10,00\xa0€/kWh', subtotal: '8,40\xa0€', subtotalWithPrecision: '8,403361344538\xa0€', subAverage: '8,40\xa0€/kWh', breakdown: [{ quantityUsed: '1 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '10,00\xa0€' }] }}
-    ${baseTiersUnitAmount} | ${1}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${false}       | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '11,90\xa0€', totalWithPrecision: '11,90\xa0€', average: '11,90\xa0€/kWh', subtotal: '10,00\xa0€', subtotalWithPrecision: '10,00\xa0€', subAverage: '10,00\xa0€/kWh', breakdown: [{ quantityUsed: '1 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '10,00\xa0€' }] }}
+    ${baseTiersUnitAmount} | ${1}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${false}       | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '11,90\xa0€', totalWithPrecision: '11,90\xa0€', average: '11,90\xa0€/kWh', subtotal: '10,00\xa0€', subtotalWithPrecision: '10,00\xa0€', subAverage: '10,00\xa0€/kWh', breakdown: [{ quantityUsed: '1 kWh', tierAmountDecimal: '11,90\xa0€/kWh', totalAmountDecimal: '11,90\xa0€' }] }}
     ${baseTiersUnitAmount} | ${1}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${false}       | ${undefined}  | ${undefined} | ${undefined}    | ${{ total: '10,00\xa0€', totalWithPrecision: '10,00\xa0€', average: '10,00\xa0€/kWh', subtotal: '10,00\xa0€', subtotalWithPrecision: '10,00\xa0€', subAverage: '10,00\xa0€/kWh', breakdown: [{ quantityUsed: '1 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '10,00\xa0€' }] }}
     ${baseTiersUnitAmount} | ${2}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${true}        | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '20,00\xa0€', totalWithPrecision: '20,00\xa0€', average: '10,00\xa0€/kWh', subtotal: '16,81\xa0€', subtotalWithPrecision: '16,806722689076\xa0€', subAverage: '8,40\xa0€/kWh', breakdown: [{ quantityUsed: '2 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '20,00\xa0€' }] }}
     ${baseTiersUnitAmount} | ${2}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${undefined}   | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '20,00\xa0€', totalWithPrecision: '20,00\xa0€', average: '10,00\xa0€/kWh', subtotal: '16,81\xa0€', subtotalWithPrecision: '16,806722689076\xa0€', subAverage: '8,40\xa0€/kWh', breakdown: [{ quantityUsed: '2 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '20,00\xa0€' }] }}
-    ${baseTiersUnitAmount} | ${2}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${false}       | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '23,80\xa0€', totalWithPrecision: '23,80\xa0€', average: '11,90\xa0€/kWh', subtotal: '20,00\xa0€', subtotalWithPrecision: '20,00\xa0€', subAverage: '10,00\xa0€/kWh', breakdown: [{ quantityUsed: '2 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '20,00\xa0€' }] }}
+    ${baseTiersUnitAmount} | ${2}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${false}       | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '23,80\xa0€', totalWithPrecision: '23,80\xa0€', average: '11,90\xa0€/kWh', subtotal: '20,00\xa0€', subtotalWithPrecision: '20,00\xa0€', subAverage: '10,00\xa0€/kWh', breakdown: [{ quantityUsed: '2 kWh', tierAmountDecimal: '11,90\xa0€/kWh', totalAmountDecimal: '23,80\xa0€' }] }}
     ${baseTiersUnitAmount} | ${2}                 | ${'kWh'}    | ${undefined} | ${'EUR'} | ${false}       | ${undefined}  | ${undefined} | ${undefined}    | ${{ total: '20,00\xa0€', totalWithPrecision: '20,00\xa0€', average: '10,00\xa0€/kWh', subtotal: '20,00\xa0€', subtotalWithPrecision: '20,00\xa0€', subAverage: '10,00\xa0€/kWh', breakdown: [{ quantityUsed: '2 kWh', tierAmountDecimal: '10,00\xa0€/kWh', totalAmountDecimal: '20,00\xa0€' }] }}
     ${baseTiersUnitAmount} | ${5}                 | ${'kWh'}    | ${'en'}      | ${'EUR'} | ${undefined}   | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '€50.00', totalWithPrecision: '€50.00', average: '€10.00/kWh', subAverage: '€8.40/kWh', subtotal: '€42.02', subtotalWithPrecision: '€42.016806722689', breakdown: [{ quantityUsed: '5 kWh', tierAmountDecimal: '€10.00/kWh', totalAmountDecimal: '€50.00' }] }}
     ${baseTiersUnitAmount} | ${15}                | ${'banana'} | ${'en'}      | ${'EUR'} | ${undefined}   | ${undefined}  | ${undefined} | ${{ rate: 19 }} | ${{ total: '€145.00', totalWithPrecision: '€145.00', average: '€9.67/banana', subAverage: '€8.12/banana', subtotal: '€121.85', subtotalWithPrecision: '€121.848739495798', breakdown: [{ quantityUsed: '10 banana', tierAmountDecimal: '€10.00/banana', totalAmountDecimal: '€100.00' }, { quantityUsed: '5 banana', tierAmountDecimal: '€9.00/banana', totalAmountDecimal: '€45.00' }] }}
diff --git a/src/tiers/compute-cumulative-value.ts b/src/tiers/compute-cumulative-value.ts
index f852041..ae37b5a 100644
--- a/src/tiers/compute-cumulative-value.ts
+++ b/src/tiers/compute-cumulative-value.ts
@@ -73,6 +73,7 @@ export const computeCumulativeValue = (
   };
 
   const breakdown: CumulativePriceBreakdownItem[] = [];
+  const taxRate = getTaxValue(tax);
 
   const total = priceTiersForQuantity.reduce(
     (total: Dinero, tier: PriceTier, index: number) => {
@@ -84,17 +85,20 @@ export const computeCumulativeValue = (
         quantity: quantityToSelectTier,
       });
       const tierAmount = toDinero(tier.unit_amount_decimal!, formatOptions.currency).multiply(graduatedQuantity);
+      const tierAmountWithTax = isTaxInclusive ? tierAmount : tierAmount.multiply(1 + taxRate);
+      const unitAmount = toDinero(tier.unit_amount_decimal!, formatOptions.currency);
+      const unitAmountWithTax = isTaxInclusive ? unitAmount : unitAmount.multiply(1 + taxRate);
 
       breakdown.push({
         quantityUsed: `${graduatedQuantity.toLocaleString(formatOptions.locale, {
           maximumFractionDigits: 6,
         })} ${formattedUnit}`,
         tierAmountDecimal: `${formatAmountFromString({
-          decimalAmount: tier.unit_amount_decimal!,
+          decimalAmount: addSeparatorToDineroString(unitAmountWithTax.getAmount().toString()),
           ...formatOptions,
         })}${formattedUnit ? `/${formattedUnit}` : ''}`,
         totalAmountDecimal: formatAmountFromString({
-          decimalAmount: addSeparatorToDineroString(tierAmount.getAmount().toString()),
+          decimalAmount: addSeparatorToDineroString(tierAmountWithTax.getAmount().toString()),
           ...formatOptions,
         }),
       });
@@ -111,7 +115,6 @@ export const computeCumulativeValue = (
       defaultValue: 'Starts at',
     });
 
-  const taxRate = getTaxValue(tax);
   const amountTotal = isTaxInclusive ? total : total.multiply(1 + taxRate);
   const amountSubtotal = isTaxInclusive ? total.divide(1 + taxRate) : total;