Unit price is negative
The net unit price (BT-146) must not be negative.
What to do now
Who has to fix this?
The issuer of the invoice has to fix this: a mandatory detail is missing. As a recipient you can reject the invoice — without the detail it is not valid under the standard.
Where this rule comes from
The BR rules form the core of EN 16931. They define which details every European e-invoice must contain — invoice number, date, parties, lines, amounts — and apply regardless of whether the invoice is exchanged as XRechnung, ZUGFeRD, Factur-X or Peppol BIS.
- Rule ID
- BR-27
- Rule set
- Basic rules of EN 16931
- Checked for
- XRechnung, ZUGFeRD, Factur-X, Peppol BIS and other EN 16931 formats
- Consequence of a violation
- The invoice is considered non-compliant with the standard and is automatically rejected by many recipients.
Does BR-27 occur in your invoice?
Upload the XRechnung or the ZUGFeRD/Factur-X PDF – the validator shows every violation with the same explanation as here. Free, no login, nothing stored.
Validate your invoice nowGeneral information, not tax or legal advice. As of October 2026. Validation rules: CEN/TC 434 (EN 16931, EUPL 1.2), KoSIT (XRechnung, Apache 2.0), FNFE-MPE/FeRD (Factur-X/ZUGFeRD, Apache 2.0), OpenPeppol AISBL (Peppol BIS), ANAF (CIUS-RO). Explanations: Billvox. Licence notices