IN-TAX-SUBTOTAL-AMOUNT:Tax subtotal amount required
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 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: 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. 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.
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 can help identify and fix this issue.
Yes, PEPPOL-EN16931-R042 is a critical error that must be fixed.
Related Errors
Last updated: 19 January 2026
Handle IN-TAX-SUBTOTAL-AMOUNT Automatically in Your Pipeline
The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.