BR-AG-08:IPSI taxable amount calculation error
Fix: Invoice Navigator automatically fixes this issue by correcting the `cbc:Percent` element in your Invoice. Upload your invoice to fix this automatically.
The IPSI taxable amount in the VAT breakdown does not match the calculated sum of line amounts plus charges minus allowances for the IPSI category.
Engine Classification
Recalculate IPSI taxable amount from sum of line amounts per EN16931 BR-AG-08
Confidence: 85% · Applied automatically in pipeline
What is BR-AG-08?
BR-AG-08 is a fatal validation rule defined in the EN 16931 specification. It validates the TaxableAmount element under TaxSubtotal[cac:TaxCategory > ID='M'] 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[cac:TaxCategory/cbc:ID='M']/cbc:TaxableAmount
Why This Error Matters
Invoice will be rejected. IPSI (Ceuta/Melilla indirect tax) transactions must follow specific rules for Spanish territory tax compliance.
BR-AG-08 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-AG-08
- ·Specification: EN 16931
How to Fix It
Calculate line total
Sum all Invoice line net amounts (BT-131) where VAT category is IPSI (M)
Add charges
Add document level charge amounts (BT-99) with IPSI category
Subtract allowances
Subtract document level allowance amounts (BT-92) with IPSI category
Update taxable amount
Set VAT category taxable amount (BT-116) to the calculated value
Before / After
<cac:TaxCategory> <cbc:Percent>999.99</cbc:Percent> <!-- Does not match expected calculation --> </cac:TaxCategory>
<cac:TaxCategory> <cbc:Percent>100.00</cbc:Percent> <!-- Matches expected calculation --> </cac:TaxCategory>
Technical Reference
//cac:TaxTotal/cac:TaxSubtotal[cac:TaxCategory/cbc:ID='M']/cbc:TaxableAmountCommon Causes
- ·IPSI taxable amount does not equal sum of line amounts
- ·VAT breakdown calculation mismatch for IPSI category
- ·Allowances/charges not properly included in IPSI base
- ·Rounding errors in IPSI taxable amount calculation
- ·Lines with IPSI rate not aggregated correctly
Seeing this in production? The API handles BR-AG-08 automatically. See the fix response →
Frequently Asked Questions
The IPSI taxable amount in the VAT breakdown does not match the calculated sum of line amounts plus charges minus allowances for the IPSI category.
Invoice Navigator automatically fixes this issue by correcting the `cbc:Percent` element in your Invoice. You can also use Invoice Navigator's compliance engine to correct this automatically in your pipeline.
Yes, BR-AG-08 is a critical error that will cause invoice rejection. It must be fixed before submission.
Many instances of BR-AG-08 can be automatically corrected using Invoice Navigator's compliance engine. The fix is applied in your pipeline with full audit evidence.
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Last updated: 27 February 2026
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