# BR-29

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

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/br-29

## Official rule text

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

## Why did my invoice fail BR-29?

When a document-level Invoicing period is given with both a start date (BT-73) and an end date (BT-74), the end date must be the same as or later than the start date. This ensures the billing period covered by the invoice is chronologically valid.

## Common causes

- Start and end dates were swapped during mapping
- End date defaulted to an earlier value or to the invoice issue date
- Timezone/format handling produced an end date before the start date

## How do I fix it?

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