IN-TAX-SUBTOTAL-AMOUNT:Tax subtotal amount required
Fix: Add TaxAmount to each TaxSubtotal. Provide the required value in the free validator.
Each VAT breakdown (TaxSubtotal) must have a tax amount specified.
Engine Classification
Business data required · Explicit input workflow · No assumptions made
Required input: Tax Subtotal Amount
What is IN-TAX-SUBTOTAL-AMOUNT?
IN-TAX-SUBTOTAL-AMOUNT is a fatal validation rule defined in the peppol-bis-3 specification. It validates the TaxAmount element under TaxTotal > 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: XPath: /Invoice/cac:TaxTotal/cac:TaxSubtotal/cbc:TaxAmount
Why This Error Matters
Tax amount required for each category.
IN-TAX-SUBTOTAL-AMOUNT is a hard failure — the invoice must be corrected and re-sent before it can reach the recipient.
Validator Behavior
- ·Causes invoice rejection
- ·Rejected by PEPPOL Access Points
- ·Error returned: IN-TAX-SUBTOTAL-AMOUNT
- ·Specification: peppol-bis-3
How to Fix It
Check TaxSubtotals
Each needs TaxAmount
Calculate
TaxableAmount × Percent / 100
XML Example
Generic example based on the rule's target XPath. Your actual XML structure may differ.
<!-- Missing or empty element triggers cbc:TaxAmount error --> <cbc:TaxAmount></cbc:TaxAmount>
<!-- Provide the required value --> <cbc:TaxAmount>VALID_VALUE</cbc:TaxAmount>
Technical Reference
XPath: /Invoice/cac:TaxTotal/cac:TaxSubtotal/cbc:TaxAmountCommon Causes
- ·Missing TaxAmount in breakdown
Seeing this in production? The API handles IN-TAX-SUBTOTAL-AMOUNT automatically. See the fix response →
Frequently Asked Questions
Each VAT breakdown must have tax amount.
Add TaxAmount to each TaxSubtotal. Invoice Navigator detects this error and prompts for the required business data before applying a safe fix.
Yes, PEPPOL-EN16931-R042 is a critical error that must be fixed.
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Last updated: 3 March 2026
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