Reference

BR-29 Invoicing period end must not precede its start

If both Invoicing period start date (BT-73) and Invoicing period end date (BT-74) are given, BT-74 shall be later than or equal to BT-73.

This is an EN 16931 core rule and a value check. The invoicing period (BG-14) tells the buyer which period was delivered or billed, for example for subscriptions or maintenance contracts. An end date before the start date usually comes from swapped fields, a date read as MM/DD instead of DD/MM during conversion, or a typo in the year. The line-level counterpart is BR-30.

Solution

Correct the dates in cac:InvoicePeriod (CII: ram:BillingSpecifiedPeriod/ram:StartDateTime and ram:EndDateTime) so the end date is on or after the start date, or remove the period if it was entered in error.

Quick actions

Validate XML Convert invoice

Valid Examples

BT-73 = 2026-01-01, BT-74 = 2026-01-31

Invalid Examples

BT-73 = 2026-01-31, BT-74 = 2026-01-01 — end before start

Code Examples

Valid XML

<cac:InvoicePeriod>
  <cbc:StartDate>2026-01-01</cbc:StartDate>
  <cbc:EndDate>2026-01-31</cbc:EndDate>
</cac:InvoicePeriod>

Invalid XML

<cac:InvoicePeriod>
  <cbc:StartDate>2026-01-31</cbc:StartDate>
  <cbc:EndDate>2026-01-01</cbc:EndDate>
</cac:InvoicePeriod>

Affected Fields

BT-73 Invoicing period start date

BT-74 Invoicing period end date

Validation Tools

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