errorEN 16931

BR-AE-08:Reverse charge taxable amount doesn't add up

The taxable amount in the reverse charge VAT breakdown does not match the sum of reverse charge line items, charges, and allowances. The taxable base must equal: sum of line amounts with category AE, plus charges with category AE, minus allowances with category AE.

Severity
Fatal
Rule set
EN 16931
Country
All EU
Fix type
AUTO-FIX
Confidence
90%
Category
calculation

Engine Classification

Recalculates the reverse charge taxable amount from AE lines, charges, and allowances

Confidence: 90% · Applied automatically in pipeline

What is BR-AE-08?

BR-AE-08 is a fatal validation rule defined in the EN 16931 specification. It validates the TaxableAmount element under TaxSubtotal in the UBL invoice XML.

When this rule fires, the invoice is non-compliant and will be rejected by Peppol access points and national validation services. The sending system receives a rejection response and the invoice does not reach the buyer.

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

Why This Error Matters

Invoice will be rejected by validation. VAT breakdown taxable amount must mathematically match the reverse charge components.

BR-AE-08 is a hard failure. Invoices that trigger this rule are rejected at the access point and never reach the recipient. In Peppol networks, this means your sending system receives an MLR (Message Level Response) with a rejection status. The invoice must be corrected and re-sent, adding delay to your payment cycle.

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-AE-08
  • ·Specification: EN 16931

How to Fix It

1.

Sum the reverse charge line items

Add up all line net amounts that use VAT category AE (reverse charge).

2.

Include charges and allowances

Add any document-level charges with category AE. Subtract any document-level allowances with category AE.

3.

Update the VAT breakdown

Set the TaxableAmount in the AE breakdown to match your calculation.

Before / After

Failing XML
<Invoice>
  <!-- Issue: In a VAT breakdown where VAT category code is Reverse charge -->
</Invoice>
Corrected XML
<Invoice>
  <!-- Issue resolved per EN 16931 -->
</Invoice>

Technical Reference

XPathcac:TaxTotal/cac:TaxSubtotal/cbc:TaxableAmount
SpecEN 16931
Operationrecalculate
StrategyRecalculates the reverse charge taxable amount from AE lines, charges, and allowances

Common Causes

  • ·Line items changed without updating VAT summary
  • ·Mixed categories in a single breakdown
  • ·Charges or allowances not categorized as AE

Seeing this in production? The API handles BR-AE-08 automatically. See the fix response →

Commonly Seen In

All invoicing software

See Also

Related Errors

Last updated: 27 February 2026

Share this guide:

Handle BR-AE-08 Automatically in Your Pipeline

The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.