# BR-13 Invoice total amount without VAT is required

An invoice shall have the Invoice total amount without VAT (BT-109), the net payable amount before VAT is added.

## Problem Description

> **ERROR**: EN 16931 core business rule (CEN)

## Context and Significance

This is an EN 16931 core rule. BT-109 is the invoice total without VAT: BT-106 minus document level allowances (BT-107) plus document level charges (BT-108), as checked by BR-CO-13. It links the line totals to the VAT breakdown (BG-23). The error appears when an export writes only the line total and the total with VAT, for example because the source document shows no net subtotal. In CII, BT-109 is ram:TaxBasisTotalAmount.

## Solution

Add cac:LegalMonetaryTotal/cbc:TaxExclusiveAmount equal to BT-106 minus document allowances plus document charges.

- [Validate XML](/en/xrechnung-validator?source=resource&rule=BR-13)
- [Convert invoice](/en/pdf-to-xrechnung?source=resource&rule=BR-13)

## Valid Examples

- BT-109 = 1000.00 — net total before VAT

## Invalid Examples

- cac:LegalMonetaryTotal has no cbc:TaxExclusiveAmount element

## Code Examples

### Valid XML
```
<cac:LegalMonetaryTotal>
  <cbc:LineExtensionAmount currencyID="EUR">1000.00</cbc:LineExtensionAmount>
  <cbc:TaxExclusiveAmount currencyID="EUR">1000.00</cbc:TaxExclusiveAmount>
  <cbc:TaxInclusiveAmount currencyID="EUR">1190.00</cbc:TaxInclusiveAmount>
</cac:LegalMonetaryTotal>
```

### Invalid XML
```
<cac:LegalMonetaryTotal>
  <cbc:LineExtensionAmount currencyID="EUR">1000.00</cbc:LineExtensionAmount>
  <cbc:TaxInclusiveAmount currencyID="EUR">1190.00</cbc:TaxInclusiveAmount>
</cac:LegalMonetaryTotal>
```

## Affected Fields

- [BT-109 Invoice total amount without VAT](/resources/xrechnung/bt-109-invoice-total-amount-without-vat)

## Related Rules

- [BR-12](/resources/kosit-validator-errors/br-12-sum-of-line-net-amount-required)
- [BR-14](/resources/kosit-validator-errors/br-14-invoice-total-with-vat-required)
- [BR-CO-13](/resources/kosit-validator-errors/br-co-13-invoice-total-without-vat-must-match-totals-chain)

## 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.