BR-DEC-20EN 16931fatalbusiness

VAT tax amount: max 2 decimals

Fix: Invoice Navigator automatically fixes this issue by correcting the `cbc:TaxAmount` element in your Invoice (BR-DEC-20). Upload your invoice to fix this automatically.

TaxSubtotal/TaxAmount allows maximum 2 decimal places.

Where is this in my invoice?

Shown on a sample invoice. The marked row is the field this rule checks; on your own invoice it sits in the same place.

Sample invoice · not your document

Invoice

SAMPLE-INV-001 · issued 4 Jan 2026 · due 4 Feb 2026 · EUR

Seller

Seller nameSample Supplier B.V.

Seller streetHerengracht 100

Seller postcode1015 BS

Seller cityAmsterdam

Seller countryNL

Seller VAT numberNL123456789B01

Seller registration number12345678

Seller electronic addressNL123456789B01

Buyer

Buyer nameSample Buyer NV

Buyer streetRue de la Loi 42

Buyer postcode1000

Buyer cityBrussels

Buyer countryBE

Buyer VAT numberBE0123456789

Buyer electronic addressBE0123456789

Invoice details

Invoice numberSAMPLE-INV-001

Issue date4 Jan 2026

Due date4 Feb 2026

Invoice type380

CurrencyEUR

Buyer referencePO-12345

Payment

Payment method30

Payment IBANNL91ABNA0417164300

Line items

No.	Item	Quantity	Unit price	VAT rate (%)	Line amount
1	Consulting Services	1	€100.00	21%	€100.00

Totals

Sum of line amounts€100.00

Total without VAT€100.00

Total VAT€21.00

Total with VAT€121.00

Amount due€121.00

VAT breakdown

VAT category	VAT rate (%)	Taxable amount	VAT amount
S	21%	€100.00	€21.00 BR-DEC-20

How to Fix It

Check tax amount

Each TaxSubtotal/TaxAmount

Round

May cause minor discrepancy with rate × base

See this rule against your own invoice: every finding is pinned to the row it concerns.

Check your invoice Run this check in CI

Severity

Fatal

Rule set

EN 16931

Country

All EU

Fix type

Auto-fix

Confidence

95%

Engine Classification

Round VAT category tax amount to 2 decimal places per EN16931

Confidence: 95% · Applied automatically in pipeline

What is BR-DEC-20?

BR-DEC-20 is a fatal validation rule defined in the EN 16931 specification. It validates the TaxAmount element under TaxSubtotal in the UBL invoice XML.

When this rule fires, the invoice is rejected by Peppol access points and never reaches the buyer.

Target path: //cac:TaxTotal/cac:TaxSubtotal/cbc:TaxAmount

Why This Error Matters

Invoice will be rejected by validation. VAT amounts must have proper precision for tax compliance and reporting.

BR-DEC-20 is a hard failure — the invoice must be corrected and re-sent before it can reach the recipient.

Invoice Navigator can automatically correct this error in your pipeline. The fix is applied with full audit evidence, so your compliance trail remains intact.

Validator Behavior

·Causes invoice rejection
·Error returned: BR-DEC-20
·Specification: EN 16931

Before / After

Failing XML

<cac:TaxSubtotal>
  <cbc:TaxAmount>100.123456</cbc:TaxAmount>
  <!-- Too many decimal places -->
</cac:TaxSubtotal>

Corrected XML

<cac:TaxSubtotal>
  <cbc:TaxAmount>100.00</cbc:TaxAmount>
  <!-- Correct decimal places -->
</cac:TaxSubtotal>

Technical Reference

XPath//cac:TaxTotal/cac:TaxSubtotal/cbc:TaxAmount

SpecEN 16931

Operationnormalize

StrategyRound VAT category tax amount to 2 decimal places per EN16931

Common Causes

·Tax rate calculation produced extra decimals
·Percentage of taxable amount created excess precision
·ERP exports calculated tax with full precision
·Rounding not applied after tax calculation
·Multiple sub-calculations summed without rounding

Seeing this in production? The API handles BR-DEC-20 automatically. See the fix response →

Frequently Asked Questions

TaxSubtotal/TaxAmount allows maximum 2 decimal places.

Round calculated VAT to 2 decimals. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.

Yes, BR-DEC-20 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-DEC-20 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues, including vat tax amount: max 2 decimals.

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