# BR-CO-18 At least one VAT breakdown is required

An invoice shall have at least one VAT breakdown group (BG-23) summarising the amounts for each VAT category.

## Problem Description

An invoice shall have at least one VAT breakdown group (BG-23) summarising the amounts for each VAT category.

> **ERROR**: XRechnung 3.0

## Context and Significance

This EN16931 core rule guarantees a VAT summary exists so tax authorities and BR-CO-14 can reconcile the total VAT amount against category-level amounts.

## Solution

Add at least one cac:TaxTotal/cac:TaxSubtotal (BG-23) with the taxable amount, VAT amount, and VAT category code.

- validate
- convert

## Valid Examples

- One BG-23 group: category S, 19 % rate, taxable 100.00, VAT 19.00

## Invalid Examples

- Invoice with a total VAT amount but no BG-23 VAT breakdown at all

## Code Examples

### Valid XML
```
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="EUR">19.00</cbc:TaxAmount>
  <cac:TaxSubtotal>
    <cbc:TaxableAmount currencyID="EUR">100.00</cbc:TaxableAmount>
    <cbc:TaxAmount currencyID="EUR">19.00</cbc:TaxAmount>
    <cac:TaxCategory>
      <cbc:ID>S</cbc:ID>
      <cbc:Percent>19</cbc:Percent>
    </cac:TaxCategory>
  </cac:TaxSubtotal>
</cac:TaxTotal>
```

### Invalid XML
```
<cac:TaxTotal>
  <cbc:TaxAmount currencyID="EUR">19.00</cbc:TaxAmount>
</cac:TaxTotal>
```

## Affected Fields

- [BG-23 VAT breakdown](/resources/xrechnung)

## Related Rules

- [BR-CO-14](/resources/kosit-validator-errors/br-co-14-invoice-total-vat-must-equal-sum-of-vat-categories)

## Validation Tools

- [Official KoSIT Validator](https://erechnungsvalidator.service-bw.de/): Validate your XRechnung files against all BR-DE rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Automatic validation error fixes when converting.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [Complete Error List](/resources/kosit-validator-errors): Overview of all German XRechnung validation rules.