All explained rules

BR-02: The invoice number is missing. How to fix it

The invoice carries no invoice number (BT-1).

Error: the invoice is refusedFrom the European norm EN 16931

The rule, in its own words

An Invoice shall have an Invoice number (BT-1).

Fields involved: BT-1

What the rule checks

The rule checks that an invoice number is present and not empty. The standard prescribes no format: digits, letters and hyphens are all allowed. All it asks is that there is one.

Why files fail it

  • The field is there but blank because no numbering series is set up.
  • The number was assigned at print time and never written into the data.
  • It is a draft or a pro-forma that was exported as an invoice by mistake.

How to fix it

  1. Assign an invoice number. It must be sequential and unique, though that is tax law rather than this rule.
  2. The field is "Invoice number" (BT-1) in the standard.
  3. Check whether your software assigns the number only at print time. If so it is in the PDF but not in the data.

Check your file

Upload your invoice. It runs through the same official validator that applies this rule, and you see immediately whether it passes now.

Check an invoice

or drop it here

XRechnung XML, or a ZUGFeRD / Factur-X PDF. Up to 10 MB.

  • Run against the official EN 16931 and XRechnung rules
  • Your file is deleted the moment the result appears
  • No sign-up, and a result in seconds

What to do next

An invoice with errors will be rejected. Build a compliant one from the PDF you already have, or enter the details yourself. Either way you get a file that passes.