Short answer
Late payment interest is calculated per day: outstanding amount × annual rate × days late / 365. For business customers, the statutory rate from July 1 to December 31, 2026 is 10.4% in the Netherlands and 10.5% in Belgium. On a €2,420 invoice paid 60 days late, that is €41.37 plus €363 in collection costs in the Netherlands, or €41.77 plus a €40 flat fee in Belgium.
How to calculate late payment interest
- Choose the country and whether your customer is a business or government body, or a consumer. Business customers pay the commercial rate; Dutch consumers pay the lower statutory rate.
- Enter the amount outstanding, including VAT. Interest and collection costs are calculated on that amount.
- Enter the due date; interest runs from the next day. If no payment term was agreed, a business customer has 30 days after receiving the invoice in both countries.
- Enter the day your customer paid, or the date to calculate until, such as the date of your reminder.
- Put the result in your reminder, with the calculation per period as support.
Statutory late payment rates since 2021
Both commercial rates are the European Central Bank’s main refinancing rate plus 8 percentage points, fixed on January 1 and July 1. Belgium rounds the result up to the next half percentage point. The Dutch consumer rate is set separately. If the arrears run into more than one period, the calculator uses the rate that applied in each one.
In the table, B2B means invoices to businesses and government bodies, and B2C invoices to consumers.
| Period | NL B2B | NL B2C | BE B2B |
|---|---|---|---|
| Jul–Dec 2026 | 10.4% | 4% | 10.5% |
| Jan–Jun 2026 | 10.15% | 4% | 10.5% |
| Jul–Dec 2025 | 10.15% | 6% | 10.5% |
| Jan–Jun 2025 | 11.15% | 6% | 11.5% |
| Jul–Dec 2024 | 12.25% | 7% | 12.5% |
| Jan–Jun 2024 | 12.5% | 7% | 12.5% |
| Jul–Dec 2023 | 12% | 6% | 12% |
| Jan–Jun 2023 | 10.5% | 4% | 10.5% |
| 2021–2022 | 8% | 2% | 8% |
Business.gov.nl: payment terms, collection charges and statutory interest
Belgian Official Gazette: rate for the second half of 2026 (in Dutch)
Compound interest in the Netherlands, simple interest in Belgium
In the Netherlands, the interest of each full year is added to the amount it is calculated over, so in the second year your customer also pays interest on the first year’s interest. In Belgium, accrued interest doesn’t earn interest by itself, so the calculator applies simple interest there.
Worked example: Dutch consumer, just over a year late
Amount outstanding: €1,000 Due date: December 31, 2024 Calculated until: January 31, 2026 January 1 to December 31, 2025: €1,000 × 6% × 365 / 365 = €60.00 New amount after one year: €1,000 + €60 = €1,060 January 1 to 31, 2026: €1,060 × 4% × 31 / 365 = €3.60 Statutory interest: €63.60
Collection costs and flat fees
In the Netherlands, the calculator applies the statutory scale for collection costs (incassokosten): 15% of the first €2,500, then a decreasing percentage, with a minimum of €40 and a maximum of €6,775. For business customers, the scale applies unless you agreed otherwise. For consumers, it is a maximum you can only charge after a 14-day letter. The amounts exclude VAT.
In Belgium, a business or government customer owes a flat €40 recovery fee, plus reasonable compensation if your recovery costs are higher. For a consumer, the calculator shows the maximum fee under Book XIX: €20 on a balance up to €150, rising with the balance above that to at most €2,000, and only if your terms provide for it.
Following up late invoices in Factuur Simpel
Factuur Simpel marks an unpaid invoice as overdue once the due date has passed and sends one reminder by default. After that, you send reminders with the outstanding amount yourself. The app doesn’t calculate interest or collection costs: work them out here and add the amounts to your reminder.
Frequently asked questions
Is interest calculated on the amount including VAT?
Yes. Interest and collection costs are calculated on the outstanding amount including VAT, because that is what your customer owes you.
What if my customer paid part of the invoice?
Calculate in parts: on the full amount up to and including the day of the partial payment, then on the amount still outstanding. In the Netherlands, a payment goes towards costs and interest first, and only then towards the principal.
Until which date do I calculate interest?
Until the day your customer pays. If you send a reminder while the invoice is still unpaid, calculate up to the date of your reminder and state that interest keeps running until payment.
Is the €40 also due on a small invoice?
Yes. In both countries, a business or government customer owes at least €40 in recovery costs on a late invoice, whatever its amount. In the Netherlands, that is the minimum of the collection cost scale; in Belgium, it is the flat fee.
Spot late invoices straight away
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Sources and further reading
- Rijksoverheid: statutory interest rates (in Dutch)
- Business.gov.nl: payment terms, collection charges and statutory interest
- Dutch Civil Code, Book 6, articles 6:119 and 6:119a (in Dutch)
- Dutch decree on extrajudicial collection costs (in Dutch)
- Belgian Official Gazette: rate for the second half of 2026 (in Dutch)
- Belgian late payment act of August 2, 2002 (in Dutch)
- Book XIX of the Code of Economic Law on consumer debts (in Dutch)