# BR-CL-18 Line-level VAT category code must come from UNCL5305

The invoiced item VAT category code (BT-151) at line level must be coded using the UNCL5305 code list.

## Problem Description

The invoiced item VAT category code (BT-151) at line level must be coded using the UNCL5305 code list.

> **ERROR**: XRechnung 3.0

## Context and Significance

This EN16931 core code-list rule ensures each line references the same category taxonomy as the document VAT breakdown.

## Solution

Set BT-151 to a UNCL5305 category such as S, Z, E, AE, K, G, O, L or M, consistent with the matching VAT breakdown.

- validate
- convert

## Valid Examples

- BT-151 = S — standard rated line
- BT-151 = Z — zero rated line

## Invalid Examples

- BT-151 = N — not a UNCL5305 category
- BT-151 = 0 — numeric value, not a category code

## Code Examples

### Valid XML
```
<cac:Item>
  <cac:ClassifiedTaxCategory>
    <cbc:ID>S</cbc:ID>
    <cbc:Percent>19</cbc:Percent>
  </cac:ClassifiedTaxCategory>
</cac:Item>
```

### Invalid XML
```
<cac:Item>
  <cac:ClassifiedTaxCategory>
    <cbc:ID>N</cbc:ID>
    <cbc:Percent>19</cbc:Percent>
  </cac:ClassifiedTaxCategory>
</cac:Item>
```

## Affected Fields

- [BT-151 Invoiced item VAT category code](/resources/xrechnung/bt-151-invoice-line-vat-category-code)

## Related Rules

- [BR-CL-17](/resources/kosit-validator-errors/br-cl-17-uncl5305-document-tax-category)
- [BR-S-1](/resources/kosit-validator-errors/br-s-1-standard-rated-line-requires-standard-rated-vat-breakdown)
- [BR-E-01](/resources/kosit-validator-errors/br-e-01-exempt-vat-breakdown-required)

## 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.