Reference

BR-30 Invoice line period end must not precede its start

If both Invoice line period start date (BT-134) and Invoice line period end date (BT-135) are given, BT-135 shall be later than or equal to BT-134.

This is an EN 16931 core rule and the line-level counterpart of BR-29. The invoice line period (BG-26) dates one line, for example a month of rent, a licence term or one billing cycle of a subscription. The error usually comes from swapped start and end dates, a misread date format or a wrong year, often on recurring lines generated from contract data.

Solution

Correct cac:InvoiceLine/cac:InvoicePeriod (CII: ram:SpecifiedLineTradeSettlement/ram:BillingSpecifiedPeriod) so the end date is on or after the start date, or remove the line period if it is not needed.

Quick actions

Validate XML Convert invoice

Valid Examples

BT-134 = 2026-02-01, BT-135 = 2026-02-28

Invalid Examples

BT-134 = 2026-02-28, BT-135 = 2026-02-01 — end before start

Code Examples

Valid XML

<cac:InvoiceLine>
  <cac:InvoicePeriod>
    <cbc:StartDate>2026-02-01</cbc:StartDate>
    <cbc:EndDate>2026-02-28</cbc:EndDate>
  </cac:InvoicePeriod>
</cac:InvoiceLine>

Invalid XML

<cac:InvoiceLine>
  <cac:InvoicePeriod>
    <cbc:StartDate>2026-02-28</cbc:StartDate>
    <cbc:EndDate>2026-02-01</cbc:EndDate>
  </cac:InvoicePeriod>
</cac:InvoiceLine>