Sending an effective payment reminder: how to get that invoice paid

By Gert Bellemans, managing director of Bizzon. Last legal review: October 2026.

A formal payment reminder is a written demand to pay an overdue invoice within a fixed period. You send it once a friendly reminder has had no effect. With a business customer (B2B) you may charge interest and compensation straight away. With a consumer (B2C) you must first send one free reminder and wait at least 14 calendar days.

In short:

Work with a fixed four-step process, so you do not have to decide again for every invoice.
Use a separate letter for B2B and for B2C; the legal rules differ considerably.
Make sure you can prove that your reminder arrived. Without proof, your position is weak.

👉 Request the free payment reminder templates

How do you send a payment reminder? A 4-step plan

Decide in advance which step you take on which day. The biggest pitfall is that every unpaid invoice becomes a new, emotional decision: “Shall I give them one more chance?” That hesitation costs time and money.

Friendly payment reminder (day 1 to 7 after the due date). Short and businesslike. State the outstanding amount, the invoice number and the payment details. No threatening language: the invoice may simply have been overlooked.
First formal reminder (day 8 to 14). Refer to your earlier reminder, set a new final payment date (usually 14 days) and point out the consequences: statutory interest and a compensation clause.
Second reminder or notice of default (day 15 to 30). The last step before handing over. State that you will pass the claim to a debt collection agency and that the additional costs are for the debtor.
Handover to a debt collection agency (from day 30). Bizzon takes over the file from € 49 per file. Clients are paid within 17 days on average.

Already sent two reminders without result? Then this is the moment to hand over. 👉 Start your file from € 49

What is the difference between a B2B and a B2C payment reminder?

A consumer is far better protected by law than a business. In B2C you must first send a free reminder and the costs are capped; in B2B you may charge interest and costs from the first day after the due date.

	Business (B2B)	Consumer (B2C)
Legal basis	Act of 2 August 2002	Book XIX of the Belgian Code of Economic Law, since 1 September 2023
Reminder mandatory?	No	Yes, one free reminder
Waiting period	None	14 calendar days; by post it starts on the third working day after sending, by e-mail on the following day
Interest	10.5% per year in 2026, from the due date	At most the reference interest rate + 8 percentage points, only after the waiting period
Compensation	Fixed sum of € 40 per invoice, plus whatever your terms provide	Up to € 150: max. € 20. From € 150.01 to € 500: € 30 + 10% of the part above € 150. Above € 500: € 65 + 5% of the part above € 500, capped at € 2,000
Tone	Businesslike and direct	Clear, without legal jargon

What must the free reminder to a consumer contain?

The first reminder must state the amount due, the compensation you will charge after the period expires, your name and company number, a description of the product or service supplied, and the payment period of 14 calendar days. You may not charge any costs for it, including file or administration fees.

What do you risk if a B2C reminder contains a mistake?

With a mistake you risk losing not only your right to costs and interest, but even your right to the principal amount. If the consumer files a complaint, the costs of the investigation are moreover borne by the party complained about. The burden of proof lies with you as the business.

That is why many business owners have their consumer files handled by a specialist. 👉 Let Bizzon handle your B2C files

Do you have to send a reminder first in B2B?

No. As soon as the payment term has expired, you may hand the claim straight to a debt collection agency. We still recommend one formal reminder: it is usually faster, cheaper and less damaging to the relationship than going straight to court.

What should a payment reminder contain?

A good payment reminder contains six elements and leaves no room for doubt:

The outstanding amount, exact, in euro.
The invoice number, with a copy of the invoice attached.
A new final payment date. In a first formal reminder, 14 days after receipt is customary.
The payment details: IBAN and the payment reference.
The consequences of non-payment: statutory interest and the compensation clause.
The next step: handover to a debt collection agency, with the additional costs for the debtor.

Rather not write it yourself? 👉 Request the ready-made templates

Do you have to send a payment reminder by registered post?

No, that is not a legal requirement. A reminder by ordinary post or by e-mail is in principle sufficient. For larger amounts or persistent non-payers, registered post is sensible, because it proves that the letter reached the debtor’s address.

Our advice: send the reminder both by registered and by ordinary post. That way your customer can never claim in court that he received nothing. Keep all correspondence and proof of sending.

Is a payment reminder by e-mail valid?

Yes. Since 1 January 2023 the new Belgian Civil Code recognises notification by electronic means as a valid means of communication. But “I sent the e-mail” is not proof. You must be able to show that the recipient has seen your e-mail.

You have that proof in two cases:

The customer has replied to your e-mail.
You have received an electronic read receipt.

Without that proof, the burden of proof lies entirely with you. In practice, a lawyer will not start a case without it. No response to your e-mail? Then follow up by post or confirm by telephone.

Tip: request a read receipt for your own invoices, reminders and notices of default, and be careful about confirming read receipts on incoming e-mails yourself.

Tired of chasing payments? Hand it over

Bizzon takes over the follow-up of your unpaid invoices from € 49 per file. You supply the invoice and your earlier reminders; we handle the communication with your customer, diplomatically and decisively.

Paid within 17 days on average
4.4 out of 5 on Google
More than 10 years of experience in debt collection for Flemish SMEs

“After 3 months I still had an outstanding invoice, and even after 4 payment reminders nothing was moving. I then came across Bizzon, and thanks to your work the invoice was paid after 1.5 weeks! Great work, so in future I know exactly where to find you.”

Wannes de Jong, Google review (translated from Dutch)

👉 Start your file from € 49 or contact us on +32 11 46 90 00.

Frequently asked questions about payment reminders

How many payment reminders do you have to send?

For a consumer, one free reminder is legally required. For a business there is no mandatory number. In practice, a process of one friendly reminder and two formal reminders works best.

May you charge costs for a payment reminder?

For a business you may do so from the first day after the due date: interest plus a fixed sum of € 40. For a consumer the first reminder is free, and only after 14 calendar days may you charge the legally capped compensation and interest.

How long do you have to wait after a payment reminder?

For a consumer at least 14 calendar days after the free reminder. For a business you set the period yourself; 14 days is customary.

What is the difference between a friendly reminder, a formal reminder and a notice of default?

A friendly reminder is a polite request to pay. A formal reminder is a demand with a final date and the consequences. A notice of default is the last formal warning before a debt collection agency or the court.

When do you call in a debt collection agency?

As soon as your reminders remain without result, usually around day 30 after the due date. For a business it is allowed as soon as the payment term has expired. At Bizzon this is possible from € 49 per file.