The short answer
When a Belgian business customer does not pay, the law of 2 August 2002 on late payment in commercial transactions is on your side. Without an agreed term, an invoice is due 30 days after the customer receives it, and an agreed term may not exceed 60 days. From the day after the due date, interest runs automatically at the reference rate plus 8 percentage points, 10.5% a year in the second half of 2026, plus a fixed 40 euros for collection costs. No formal notice is needed for either. In practice you send a friendly reminder (aanmaning), then a formal notice (ingebrekestelling) with a final deadline. If the customer does not contest the debt, your lawyer can have a bailiff collect it without a court case. If the customer contests it, the enterprise court decides.
The rules below come from the law of 2 August 2002, the Civil Code and the Judicial Code on Justel, and from FPS Economy, read on 1 October 2026. This is general information for sales and credit teams, not legal advice.
Payment terms: what the law allows
Rule | Between businesses | Public authority as debtor |
|---|---|---|
No term agreed | 30 calendar days from the day after the invoice is received | 30 calendar days |
Longest term you may agree | 60 calendar days since 1 February 2022; a longer clause is treated as not written | 60 calendar days, only if objectively justified |
Acceptance or inspection period | Counts inside the payment term | Counts inside the payment term |
Late interest | Reference rate plus 8 points, unless fairly agreed otherwise | Reference rate plus 8 points, always |
Fixed compensation | 40 euros, automatically | 40 euros, automatically |
Interest and the 40 euros, worked out
The Minister of Finance publishes the rate each half-year in the Official Gazette. It follows the European Central Bank's main refinancing rate on 1 January or 1 July: 2.40% on 1 July 2026, after the ECB decision effective 17 June 2026. Add 8 points, round up to the next half point, and you get 10.5% for July to December 2026.
Interest runs on the amount due including VAT. For example, an invoice of 12,100 euros including VAT paid 45 days late in the second half of 2026 carries 12,100 x 10.5% x 45/365 = 156.64 euros of interest, plus the fixed 40 euros. Other collection costs can be claimed on top as reasonable compensation.
Reminder or formal notice?
Reminder (aanmaning, herinnering) | Formal notice (ingebrekestelling) | |
|---|---|---|
What it is | A friendly nudge | A clear, unambiguous demand to pay |
Legal basis | None required | Civil Code, Book 5, articles 5.231 to 5.233, in force since 1 January 2023 |
Needed for interest on a B2B invoice? | No | No: under the 2002 law interest and the 40 euros run without it |
Why send it anyway | Many late payers simply forgot | It proves you demanded payment, can trigger clauses in your terms, and precedes a bailiff or court |
How | Email or phone | Registered letter plus email, with a final deadline |
The consumer rules do not apply to your business customers
Search for "aanmaning" and you will find a mandatory free first reminder, a 14-day waiting period and capped penalties. Those come from Book XIX of the Code of Economic Law, in force since 1 September 2023, and FPS Economy describes them as rules for consumer debts. For an invoice to a company, the 2002 law applies: no free reminder is required. A polite first reminder is still good practice.
A timeline that works
Day 1 after the due date: check the invoice arrived and is correct. Call the person who ordered.
Day 3 to 7: send the reminder below.
Day 15 to 20: send the formal notice by registered letter, with a final deadline of 8 to 15 days. Hold new deliveries or ask for prepayment.
After the deadline: uncontested, ask your lawyer for the bailiff procedure; contested, weigh court against the amount.
How to keep invoices from going overdue in the first place is in credit management and DSO.
Template: payment reminder
Subject: Reminder: invoice [number] of [date]
Dear [name],
Invoice [number] of [date] for [amount] euros, due on [due date], has not been paid yet. If your payment has crossed this message, please disregard it. If not, could you transfer the amount to [IBAN] with reference [structured communication] within 7 days? If something is wrong with the invoice or delivery, let me know.
Kind regards, [name], [company], enterprise number [number]
Template: formal notice
Subject: Formal notice: invoice [number]
Dear Sir or Madam,
Despite our reminder of [date], invoice [number] of [date] for [amount] euros, due on [due date], remains unpaid.
We hereby give you formal notice to pay within 8 days of this letter: the principal of [amount] euros; interest from [day after the due date] at the rate for commercial transactions (10.5% a year in the second half of 2026), under article 5 of the law of 2 August 2002; and the fixed compensation of 40 euros under article 6 of that law.
Without payment by then, we will pass the file to our lawyer and a bailiff without further notice, including for the procedure for uncontested debts (articles 1394/20 and following of the Judicial Code), at your cost as far as the law allows.
Yours faithfully, [name], [position], [company], enterprise number [number]
Uncontested debts: collection through a bailiff
Since 2 July 2016, articles 1394/20 to 1394/27 of the Judicial Code let a business collect an uncontested, certain and payable money debt from another business without a court case.
Your lawyer instructs a bailiff. The procedure starts at the request of the creditor's lawyer.
The bailiff serves a summons to pay with every amount justified, copies of your evidence and a response form. The customer has one month.
Paying or contesting ends it; after a contest you can still go to court. An agreed payment plan suspends it.
No reaction: at the earliest eight days after the month, the bailiff draws up a record of non-contestation, which a magistrate declares enforceable. It then works like a judgment.
The customer can still suspend enforcement by applying to court within one month of service.
Any amount qualifies, but interest and penalty clauses are capped at 10% of the principal in this procedure. Excluded: public authorities; parties not in the KBO or, since 26 February 2026, not in an EU business register linked to it; acts outside the business; most non-contractual claims; and customers in bankruptcy, judicial reorganisation or another collective procedure. So check the status first: how to check whether a Belgian company is bankrupt, and what judicial reorganisation means for your invoices.
Collection agencies
An incassobureau collects amicably: letters, calls, payment plans. It cannot seize anything; only a bailiff with an enforceable title can. FPS Economy requires prior registration for anyone collecting consumer debts, with professional liability insurance and a third-party account, and publishes the list of registered collectors. Its pages describe no such duty for debts between businesses, but the list is a useful filter when you choose an agency.
Going to court
A dispute between businesses goes to the enterprise court (ondernemingsrechtbank) whatever the amount; the justice of the peace, competent up to 5,000 euros, does not hear disputes between enterprises. A judgment can award principal, interest, the 40 euros, reasonable collection costs and the procedural indemnity, which a bailiff then enforces.
Before you deliver to a late payer again
An unpaid invoice is often the first private sign of trouble that public filings show in other ways. Before the next order, check the customer's legal status, filed accounts and recent publications. Bizzy puts these on one record for Belgian companies: legal status, legal form and establishments from the KBO, four years of filed accounts from the National Bank with equity, cash and working capital, and Official Gazette publications by type, such as a director resigning. You can start for free. What to look for is in how to spot a customer heading for trouble and how to run a company credit check.
Frequently asked questions
Do I have to send a free reminder before charging interest to a business customer? No. Under the 2002 law, interest and the 40 euros are due automatically from the day after the due date. The free reminder is a consumer rule.
Can I agree 90-day payment terms with a Belgian business customer? Not validly. Since 1 February 2022 the maximum is 60 calendar days, unless a royal decree allows more for your sector.
Is the 40 euros due per invoice? The law attaches it to each outstanding amount on which late interest is due, so in practice to each late invoice. Higher collection costs can be claimed on top as reasonable compensation.
What if the customer disputes the invoice? Then the bailiff procedure is closed and the claim goes to the enterprise court. Keep the order, delivery note and any written acceptance as evidence.
Photo: the market square of Oudenaarde with the town hall, Spotter2, CC BY-SA 4.0, via Wikimedia Commons