# BR-S-09 Standard-rated VAT amount must equal taxable amount times rate

The VAT category tax amount (BT-117) in a VAT breakdown (BG-23) where the VAT category code (BT-118) is "Standard rated" shall equal the VAT category taxable amount (BT-116) multiplied by the VAT category rate (BT-119).

## Problem Description

> **ERROR**: EN 16931 VAT category rule

## Context and Significance

This EN16931 rule checks the arithmetic of each category S VAT breakdown so the declared VAT matches the taxable base and rate. The validator accepts a difference below 1.00. In practice, a larger gap appears when the software sums VAT per line, applies a document discount after the VAT calculation, or writes the gross amount into BT-116.

## Solution

Compute BT-117 for each S breakdown as BT-116 × BT-119 / 100, round it to two decimals and write it into the TaxAmount of that TaxSubtotal. Do not add up VAT amounts that were rounded per line.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-S-09)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-S-09)

## Valid Examples

- BT-116 = 100.00, BT-119 = 19, BT-117 = 19.00

## Invalid Examples

- BT-116 = 100.00, BT-119 = 19, but BT-117 = 21.00

## Code Examples

### Valid XML
```
<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:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:TaxCategory>
</cac:TaxSubtotal>
```

### Invalid XML
```
<cac:TaxSubtotal>
  <cbc:TaxableAmount currencyID="EUR">100.00</cbc:TaxableAmount>
  <cbc:TaxAmount currencyID="EUR">21.00</cbc:TaxAmount>
  <cac:TaxCategory><cbc:ID>S</cbc:ID><cbc:Percent>19</cbc:Percent><cac:TaxScheme><cbc:ID>VAT</cbc:ID></cac:TaxScheme></cac:TaxCategory>
</cac:TaxSubtotal>
```

## Affected Fields

- [BT-116 VAT category taxable amount](/resources/xrechnung/bt-116-vat-category-taxable-amount)
- [BT-117 VAT category tax amount](/resources/xrechnung/bt-117-vat-category-tax-amount)
- [BT-118 VAT category code](/resources/xrechnung/bt-118-vat-category-code)
- [BT-119 VAT category rate](/resources/xrechnung/bt-119-vat-category-rate)

## Related Rules

- [BR-S-1](/resources/kosit-validator-errors/br-s-01-standard-rated-items-require-standard-rated-vat-breakdown)
- [BR-S-8](/resources/kosit-validator-errors/br-s-08-standard-rated-taxable-amount-must-match-lines-charges-allowances)
- [BR-CO-18](/resources/kosit-validator-errors/br-co-18-vat-breakdown-required)

## 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.