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`BR-CO-13`:Tax amount calculation error

The VAT amount must equal TaxableAmount × Rate / 100 (with rounding).

Fix this in your source system

MANUAL

Tax amount calculations have legal compliance implications. The calculated tax must match your tax determination rules and rates.

See the step-by-step instructions below to fix this error manually.

Why This Error Matters

Invoice rejected. Tax exclusive amount is the basis for VAT calculation and must be mathematically correct.

How to Fix It

Calculate

TaxableAmount × Percent ÷ 100

Round

Round to 2 decimal places (half-up)

Verify total

Sum of TaxAmount must equal TaxTotal

Before & After Fix(BR-CO-13)

Before (Invalid)

Lines: 1000, Allowances: 50, Charges: 25, but TaxExclusive shows 1000 (should be 975)

After (Valid)

Lines: 1000, Allowances: 50, Charges: 25, TaxExclusive = 975

Before (Invalid)

Lines: 1000, Allowances: 50, Charges: 25, but TaxExclusive shows 1000 (should be 975)

After (Valid)

Lines: 1000, Allowances: 50, Charges: 25, TaxExclusive = 975

Compare the invalid XML structure with the corrected version. The fix ensures compliance with validation rules.

Code Example

<cac:TaxSubtotal>
  <cbc:TaxableAmount currencyID="EUR">1000.00</cbc:TaxableAmount>
  <cbc:TaxAmount currencyID="EUR">210.00</cbc:TaxAmount>
  <!-- 1000.00 × 21% = 210.00 ✓ -->
  <cac:TaxCategory>
    <cbc:ID>S</cbc:ID>
    <cbc:Percent>21</cbc:Percent>
  </cac:TaxCategory>
</cac:TaxSubtotal>

Technical Details

XPath: /Invoice/cac:LegalMonetaryTotal/cbc:PayableAmount

Common Causes

Tax exclusive amount calculation incorrect
BT-109 does not equal lines - allowances + charges
TaxExclusiveAmount formula mismatch
Manual total override broke calculation chain
Allowances/charges not factored into subtotal

Commonly Seen In

All invoicing software

Frequently Asked Questions

The VAT amount must equal TaxableAmount × Rate / 100 (with rounding).

Verify TaxAmount = TaxableAmount × Percent ÷ 100. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.

Yes, BR-CO-13 is a critical error that will cause invoice rejection. It must be fixed before submission to ensure your invoice is accepted by the recipient's system.

Many instances of BR-CO-13 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues, including tax amount calculation error.

BR-CO-13 is commonly seen in exports from All invoicing software. These software packages sometimes generate invoices that need adjustment to meet full compliance standards.

Related Errors

BR-CO-10

Sum of VAT category amounts incorrect

BR-CO-14

Tax subtotal taxable amount mismatch

Last updated: 18 January 2026

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BR-CO-13:Tax amount calculation error