# BR-DEC-25 Invoice line allowance base amount must not exceed two decimal places

The BT-137 Invoice line allowance base amount is limited to a maximum of two decimal places. Any value carrying three or more fractional digits fails EN16931 validation.

## Problem Description

The BT-137 Invoice line allowance base amount is limited to a maximum of two decimal places. Any value carrying three or more fractional digits fails EN16931 validation.

> **ERROR**: XRechnung 3.0

## Context and Significance

This is an EN16931 core decimal-precision constraint enforced by KoSIT: every monetary amount in the invoice must be expressed with no more than two decimals.

## Solution

Round BT-137 to two decimal places before serialising the amount, and apply the same rounding used in the BR-CO total and sum calculations so the invoice still reconciles.

- validate
- convert

## Valid Examples

- BT-137 = 100.00 — two decimals accepted

## Invalid Examples

- BT-137 = 100.000 — three decimals rejected

## Code Examples

### Valid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>false</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">5.00</cbc:Amount>
  <cbc:BaseAmount currencyID="EUR">100.00</cbc:BaseAmount>
</cac:AllowanceCharge>
```

### Invalid XML
```
<cac:AllowanceCharge>
  <cbc:ChargeIndicator>false</cbc:ChargeIndicator>
  <cbc:Amount currencyID="EUR">5.00</cbc:Amount>
  <cbc:BaseAmount currencyID="EUR">100.000</cbc:BaseAmount>
</cac:AllowanceCharge>
```

## Affected Fields

- [BT-137 Invoice line allowance base amount](/resources/xrechnung/bt-137-invoice-line-allowance-base-amount)

## Related Rules

- [BR-DEC-24](/resources/kosit-validator-errors/br-dec-24-invoice-line-allowance-amount-max-two-decimals)

## 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.