BR-02
The invoice has no invoice number (BT-1).
ErrorEN 16931UBLCII
Why it happens
The number is empty, whitespace-only, or the element was omitted. A blank string does not satisfy the rule.
How to fix it
Set BT-1 — cbc:ID in UBL, ram:ID in CII. It must be unique within your sales ledger; receivers use it for duplicate detection.
The official rule
EN 16931, EnglishAn Invoice shall have an Invoice number (BT-1).
Technical detail — where the rule is evaluated and the exact test
| Syntax | Context and assertion |
|---|---|
| UBL | /ubl:Invoice | /cn:CreditNote |
normalize-space(cbc:ID) != '' | |
| CII | /rsm:CrossIndustryInvoice |
normalize-space(rsm:ExchangedDocument/ram:ID) != '' |
Check your own invoice
Paste or drop your UBL or CII file into the free validator. It runs the official EN 16931 ruleset plus the German XRechnung layer and lists every rule that fires, BR-02 included — no signup, no limit.
Validate an e-invoice freeFixing the data at source instead? The CSV converter builds a compliant invoice from a spreadsheet export.