# Prepayments and previously paid amounts

Prepayments need to be shown separately so the final payable amount can be calculated correctly.

## What you may see

- Prepaid amount must be non-negative
- Prepaid amount exceeds invoice total
- Prepayment reference is missing
- Previously paid amount affects the amount due

## What this means

Some invoices include an amount that has already been paid, such as a deposit, advance payment, or partial payment. The e-invoice must show that amount separately so the final amount due can be calculated correctly.

## What to check

- The invoice total including VAT
- The amount already paid
- The amount still due
- Any previous invoice, deposit, order, or payment reference
- Whether the source invoice is a credit note instead of a normal invoice