BR-CO-17: VAT category tax amount is incorrect
In the VAT breakdown (BG-23), the category tax amount (BT-117) does not equal the taxable amount (BT-116) multiplied by the rate (BT-119) divided by 100, rounded to two decimals. Together with BR-CO-15 this is the most common VAT rounding error.
Last updated: 2026-07-07
Affected field
BT-117 VAT category tax amount / cac:TaxSubtotal/cbc:TaxAmount (UBL) / ram:ApplicableTradeTax/ram:CalculatedAmount (CII)
Cause
VAT was calculated per line and then summed, while the rule requires base × rate at breakdown level. The two methods diverge by one or more cents as soon as line-level rounding accumulates.
Fix
Recalculate BT-117 = round(BT-116 × BT-119 / 100, 2 decimals) for every category in the breakdown. Then adjust the VAT total (BT-110) and the total with VAT (BT-112) accordingly — otherwise BR-CO-15 fires next.
<cac:TaxSubtotal> <!-- ERROR: 1000.00 × 20% = 200.00, not 199.98 --> <cbc:TaxableAmount currencyID="EUR">1000.00</cbc:TaxableAmount> <cbc:TaxAmount currencyID="EUR">199.98</cbc:TaxAmount> <cac:TaxCategory><cbc:Percent>20</cbc:Percent></cac:TaxCategory> </cac:TaxSubtotal>
<cac:TaxSubtotal> <cbc:TaxableAmount currencyID="EUR">1000.00</cbc:TaxableAmount> <cbc:TaxAmount currencyID="EUR">200.00</cbc:TaxAmount> <cac:TaxCategory><cbc:Percent>20</cbc:Percent></cac:TaxCategory> </cac:TaxSubtotal>
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Frequently asked questions
My per-line VAT is correct — why the error?▼
EN 16931 mandates the calculation at breakdown level: category taxable amount × rate, rounded to 2 decimals. If your software sums line-level VAT instead, the accumulated rounding difference triggers BR-CO-17. Switch VAT calculation to "on totals" rather than "per line" where possible.
Is there any tolerance?▼
The rule accepts standard commercial rounding to two decimals on the base × rate product. Any deviation beyond that (even €0.01 from a different calculation method) is flagged.