BR-CO-20: If Invoice line period is used, the Invoice line period…

StandardEN 16931-1 (European e-invoicing semantic model)SeverityError: the invoice is rejectedSyntaxUBL, CIIBusiness terms

BG-26 Invoice line period
BT-134 Invoice line period start date
BT-135 Invoice line period end date

Applies toEvery EN 16931 invoice: XRechnung, ZUGFeRD 2.x / Factur-X (profiles EN 16931, EXTENDED, XRECHNUNG), Peppol BIS Billing 3.0, and national CIUS such as the Dutch NLCIUS or the Italian/Spanish profiles.

Official rule text

[BR-CO-20] If Invoice line period (BG-26) is used, the Invoice line period start date (BT-134) or the Invoice line period end date (BT-135) shall be filled, or both.

Why this error occurs

This rule only applies when another field has a certain value (for example a payment means code or an invoice type). Your file triggers the condition but does not provide the data that then becomes mandatory, or provides data that is then forbidden.

How to fix it

Either change the triggering value so the condition no longer applies, or add/remove the dependent elements as the rule text describes. Check the condition in the XPath test above to see exactly which value triggers it.

What the validator checks

Checked element (context):

UBL

cac:InvoiceLine/cac:InvoicePeriod | cac:CreditNoteLine/cac:InvoicePeriod

Test (XPath):

exists(cbc:StartDate) or exists(cbc:EndDate)

CII

//ram:SpecifiedLineTradeSettlement/ram:BillingSpecifiedPeriod

Test (XPath):

(ram:StartDateTime) or (ram:EndDateTime)

Check your invoice

Drop your XML or PDF on the validator and every failed rule is linked to its page here. Free, no account, the file is not stored.

Check your invoice →

Same check via API:

curl -F file=@invoice.xml https://einvoicechecker.com/v1/validate

Related rules

BR-30 If both Invoice line period start date and Invoice line period end date are given then…
BR-CO-03 Tax point date and tax point date code both given
BR-CO-04 Invoice line without VAT category code (BT-151)
BR-CO-05 Document level allowance reason code and Document level allowance reason shall…
BR-CO-06 Document level charge reason code and Document level charge reason shall indicate the…
BR-CO-07 Invoice line allowance reason code and Invoice line allowance reason shall indicate…
BR-CO-08 Invoice line charge reason code and Invoice line charge reason shall indicate the same…
BR-CO-09 VAT identifier has no valid country prefix

Frequently asked questions

What does BR-CO-20 mean?

BR-CO-20 is a en 16931 core rule: If Invoice line period (BG-26) is used, the Invoice line period start date (BT-134) or the Invoice line period end date (BT-135) shall be filled, or both.

Will my invoice be rejected because of BR-CO-20?

Yes. BR-CO-20 is flagged "fatal"; validators (KoSIT, Peppol access points, the German ZRE/OZG-RE portals) reject the invoice until it is fixed.

Which formats does BR-CO-20 apply to?

Every EN 16931 invoice: XRechnung, ZUGFeRD 2.x / Factur-X (profiles EN 16931, EXTENDED, XRECHNUNG), Peppol BIS Billing 3.0, and national CIUS such as the Dutch NLCIUS or the Italian/Spanish profiles. Syntax: UBL and CII.

Source: EN 16931-1:2017 schematron (CEN TC434, via Peppol BIS 3.0.20). Catalogue generated from the official schematron on 2026-10-14.

BR-CO-20: If Invoice line period is used, the Invoice line period start date or the Invoice line…