Requesting an advance from a Belgian business customer? Keep four things separate: the agreement, the document issued, the payment actually received and the outstanding balance. An amount on a quotation or a bank receipt does not, by itself, establish how the full invoicing chain should be handled.
Can an advance invoice be sent through Peppol?
Technically, yes: Peppol BIS Billing supports prepayment processes and document code 386 for a prepayment invoice. The standard can also represent a payment already received on an invoice. These are different situations: the advance-invoice code is not the paid-amount field.
For an invoice within the Belgian obligation, the structured format still applies. The official B2B FAQ explains the general rules and Peppol as the default exchange route. Calling a document an “advance” does not create an exception by itself. Whether and when you must issue an invoice, and when VAT becomes due, require assessment of your specific case.
Ask these three questions first
| Question | What should you check? |
|---|---|
| Is this an agreement, a payment request or an issued invoice? | Identify the document and the agreed supply. Do not rely only on the filename. |
| Has the advance been paid? | Find the payment received and match it to the correct customer and order. A requested amount is not a receipt. |
| Have advance invoices already been issued? | Gather their numbers, amounts and payment statuses before preparing the final settlement. Agree the treatment with your accountant. |
Example: checking the payment balance
The paid amount, BT-113 concerns amounts already paid in advance. Rule BR-CO-16 connects this amount with the remaining payment due.
This example checks the payment balance of one partially paid invoice, with no separate advance invoices already issued. There is no rounding adjustment:
| Item | Amount |
|---|---|
| Invoice total including VAT | €1,210 |
| Advance payment actually received | €363 |
| Amount still due | €847 |
The calculation is 1210 − 363 = 847. It illustrates only the payment balance, not a template for the VAT taxable amount or the accounting of advance invoices already issued. Do not subtract an advance again if the chosen settlement has already accounted for it. Have the full document chain checked where several advances or different VAT treatments are involved.
Check the file before sending
- Keep the agreement and order or quotation reference with the documents.
- Record each advance: invoice number if any, amount, amount paid and receipt date.
- Check that the settlement matches the earlier documents and payments.
- Compare the amount due in the structured invoice and its readable presentation. Editing only a PDF does not correct the structured data.
- Keep the sent version and discuss an already transmitted error with the recipient; avoid requesting the same payment twice.
Also read about UBL, XML and PDF and correcting an incorrect invoice. Check how your software handles advances and payments received. This article is not a complete Belgian VAT manual. To organise your invoicing, explore Cleero’s plans.