What it means
Every line (BG-25) must contain exactly one cac:ClassifiedTaxCategory inside its item (cac:Item). It holds the line's VAT category code (BT-151) and, for most categories, the VAT rate (BT-152). A line with none, or with two or more, fails. The check applies to credit note lines (cac:CreditNoteLine) in the same way.
Why it matters
EN 16931 requires exactly one VAT category block for each invoice or credit note line.
How to fix it
In your invoicing software, open the line and check that it has one VAT category. If a product is partly taxed at one rate and partly at another, enter it as two lines. If you build the XML yourself, put exactly one cac:ClassifiedTaxCategory in cac:Item of each line.
Once the file is corrected, check it again for free: Validate an invoice against EN 16931
Or fix the invoice in a form and download the corrected file, for 1 credit: Fix a rejected e-invoice
The rule as published
Invoice lines shall have one and only one classified tax category. Where this rule applies
| Rule set | Version |
|---|---|
| EN 16931 (UBL) | 1.3.17 |
| EN 16931 (UBL credit note) | 1.3.17 |
| XRechnung 3.0 (UBL) | 3.0.2 |
| XRechnung 3.0 (UBL credit note) | 3.0.2 |
| Peppol BIS Billing 3.0 (invoice) | 2026.5 |
| Peppol BIS Billing 3.0 (credit note) | 2026.5 |
| SI-UBL 2.0 / NLCIUS (invoice) | 2.0.3.13 |
| SI-UBL 2.0 / NLCIUS (credit note) | 2.0.3.13 |
| France CTC (UBL invoice) | 1.4.0-04 |
| France CTC (UBL credit note) | 1.4.0-04 |
| CIUS-RO UBL Invoice 1.0.9 | 1.0.9 |
| CIUS-RO UBL Credit Note 1.0.9 | 1.0.9 |
Check your file
Drop your e-invoice to see whether UBL-SR-48 still fails, and which other rules do.
Related rules
- UBL-SR-49 The VAT point date code can only be given once
- UBL-SR-50 A line can have only one item description
- UBL-SR-51 An address can have only one third address line
- UBL-SR-52 A line can have only one document reference
- UBL-SR-53 Tax scheme entries need both a scheme code and a number
- UBL-SR-54 An invoice can have only one payment card account