What it means
The item price discount (BT-147) is an amount taken off the item's gross price (BT-148) to arrive at the net unit price (BT-146). Each line may state it once, in cac:Price/cac:AllowanceCharge/cbc:Amount. The test counts all amounts at that path within the line, regardless of cbc:ChargeIndicator. It is different from a discount on the line total (BG-27).
Why it matters
The recipient can recalculate the unit price from the gross price and the discount.
How to fix it
Add the price discounts together and enter them once, so that the gross price minus the discount matches the net unit price. Or give only the net unit price and leave the price discount out. If the extra reduction applies to the line total, enter it as a line discount instead. In the XML, each cac:InvoiceLine or cac:CreditNoteLine may contain at most one cac:Price/cac:AllowanceCharge/cbc:Amount.
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
Item price discount shall occur maximum once 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-37 still fails, and which other rules do.
Related rules
- UBL-SR-39 An invoice can have only one project reference
- UBL-SR-40 The buyer can have only one trade name
- UBL-SR-42 A seller can have at most two tax scheme entries
- UBL-SR-43 Only the invoiced object reference may carry a scheme identifier
- UBL-SR-44 An invoice can have only one payment reference
- UBL-SR-45 Only one due date in the payment means