# BR-CO-3 Value added tax point date and date code are mutually exclusive

The Value added tax point date (BT-7) and the Value added tax point date code (BT-8) cannot both be present on the same invoice. Provide at most one of them; neither is mandatory.

## Problem Description

> **ERROR**: EN 16931 calculation and consistency rule (BR-CO)

> **Where BR-CO-03 is checked**
>
> A validator checks an e-invoice in stages. First the file must be well-formed XML that matches the UBL or CII schema (XSD). Then the EN 16931 business rules run: BR core rules, BR-CO calculations, BR-CL code lists, BR-DEC decimals and VAT-category rules such as BR-S. Next come the national or network rules that BT-24 selects: BR-DE for XRechnung, PEPPOL-EN16931 for Peppol BIS Billing. The report lists every failed rule: one error means reject, warnings alone still mean accept. BR-CO-03: EN 16931 calculation rule, reported in the stage “EN 16931 rules”.

## Context and Significance

EN 16931 lets the issuer state the VAT point either as an explicit date (BT-7) or as a code that points to another date (BT-8, for example the invoice date). Both at once would make the VAT point ambiguous. The error usually occurs when an ERP export fills both fields by default, for example a tax point date plus a fixed date code in the invoicing period.

## Solution

Remove either BT-7 or BT-8. In UBL, BT-7 is cbc:TaxPointDate and BT-8 is cac:InvoicePeriod/cbc:DescriptionCode; in CII, they are ram:TaxPointDate and ram:DueDateTypeCode in ram:ApplicableTradeTax.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-CO-3)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-CO-3)

## Valid Examples

- BT-7 = 2026-03-31, BT-8 absent
- BT-8 = 3 (invoice date), BT-7 absent
- Neither BT-7 nor BT-8 present (both are optional)

## Invalid Examples

- BT-7 = 2026-03-31 and BT-8 = 35 set on the same invoice
- UBL: cbc:TaxPointDate (BT-7) and cac:InvoicePeriod/cbc:DescriptionCode (BT-8) both filled

## Affected Fields

- [BT-7 Value added tax point date](/resources/xrechnung/bt-7-vat-point-date)
- [BT-8 Value added tax point date code](/resources/xrechnung/bt-8-vat-point-date-code)

## Related Rules

- [BR-CL-06](/resources/kosit-validator-errors/br-cl-06-untdid-2005-vat-point-date)

## Validation Tools

- [Official KoSIT Validator](https://github.com/itplr-kosit/validator): Run the official KoSIT validator with the XRechnung configuration to check EN 16931 and XRechnung rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Find validation errors during conversion and review each correction.

## Related Resources

- [Official Specification](https://docs.peppol.eu/poacc/billing/3.0/rules/ubl-tc434/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [All validation errors](/resources/kosit-validator-errors): Overview of the EN 16931, XRechnung and Peppol validation rules explained here.