What it means
The invoice line period (BG-26) gives the dates a line covers, for example one month of a rental. Its date fields are the start date (BT-134) and end date (BT-135). Each line may have only one period, in cac:InvoicePeriod.
Why it matters
The period tells the recipient which dates the line relates to.
How to fix it
If a service covers two separate periods, split it into two lines, one per period, each with its own dates. If one of the periods was added by mistake, delete it in your invoicing software. In the XML, each cac:InvoiceLine or cac:CreditNoteLine may contain at most one cac:InvoicePeriod.
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 line period 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-36 still fails, and which other rules do.
Related rules
- UBL-SR-37 A line can have only one price discount
- 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