# PEPPOL-EN16931-R120

> Invoice line net amount (BT-131) must equal Invoiced quantity (BT-129) x (Item net price (BT-146) / item price base quantity (BT-149)), plus line-level charges minus allowances. Recheck the line's cbc:LineExtensionAmount.

Checked against Peppol BIS Billing 3.0 2026.5

Canonical: https://einvoicecheck.eu/rules/peppol-en16931-r120

## Official rule text

Invoice line net amount MUST equal (Invoiced quantity * (Item net price/item price base quantity) + Sum of invoice line charge amount - sum of invoice line allowance amount

## Why did my invoice fail PEPPOL-EN16931-R120?

The Invoice line net amount (BT-131) must equal the invoiced quantity (BT-129) times the net price per base quantity (BT-146 / BT-149), plus line-level charges (BT-141) minus line-level allowances (BT-136). This arithmetic check guarantees the line total is internally consistent with its quantity, price, and line-level adjustments.

## Common causes

- Item price base quantity (BT-149) was ignored, so quantity was multiplied by the raw price.
- Line allowance or charge amounts were omitted or double-counted in the net amount.
- Rounding was applied inconsistently between the price calculation and the stored LineExtensionAmount.

## How do I fix it?

```
Recompute LineExtensionAmount: for qty 10, price 9.50 per base 1, plus 5.00 charge, minus 2.00 allowance => <cbc:LineExtensionAmount currencyID="EUR">98.00</cbc:LineExtensionAmount>.
```