Two different statutory rates
Belgium has two interest rates that apply when a debt is paid late:
- Legal interest (wettelijke interest / intérêt légal) applies to ordinary civil debts and to consumers. It is set per calendar year: 5.75% in 2024, 4.5% in 2025 and 4.5% in 2026.
- Commercial late-payment interest (Law of 2 August 2002 on late payment in commercial transactions) applies between businesses and to public authorities. It is set per semester: 11.5% in the first half of 2025, then 10.5% from 1 July 2025 through the second half of 2026.
The tool stores the official rate tables and splits a period automatically wherever the rate changes, so each segment uses its own rate.
Worked examples
Legal interest, € 10,000.00, 2024-10-01 → 2025-03-31
2024-10-01 – 2024-12-31 92 days × 5.75% € 144.93
2025-01-01 – 2025-03-31 90 days × 4.50% € 110.96
Total € 255.89
B2B late payment, € 2,500.00, 2025-04-01 → 2025-09-30
2025-04-01 – 2025-06-30 91 days × 11.5% € 71.68
2025-07-01 – 2025-09-30 92 days × 10.5% € 66.16
Total € 137.84Interest is simple (not compounded) and calculated per day on a 365-day year: principal × rate × days ÷ 365, rounded per segment.
Edge cases
- Which rate applies depends on the parties and the contract: an invoice between two companies normally uses the commercial rate; a contract can set its own rate or a fixed indemnity clause.
- Start date. Commercial interest runs automatically from the day after the agreed payment term (by default 30 days after receipt of the invoice); legal interest usually runs from a formal notice of default.
- Both end dates count. The examples include the first and last day of each segment.
- Future periods. Rates that are not yet published are never guessed: a period beyond the stored table is refused.
The page also shows the recent Statbel health index (base 2025 = 100). Count deadlines with the working days calculator, index amounts with the indexation calculator, or put the total on a reminder with a payment QR code.
Frequently asked questions
What is the Belgian legal interest rate in 2026?
The legal interest rate for 2026 is 4.5%, the same as in 2025. It applies to ordinary debts and consumers, unless a contract provides otherwise.
What is the late-payment interest rate between companies?
The commercial late-payment rate under the Law of 2 August 2002 is set per semester. It is 10.5% from 1 July 2025 through the second half of 2026.
How is the interest calculated?
As simple interest per day: principal times the annual rate times the number of days divided by 365, calculated separately for each period with a different rate.
What happens when the rate changes during the period?
The period is split at each rate change and every segment is calculated with its own rate, then the segments are added up.
Does the tool include the 40 euro recovery fee?
No. It calculates interest only. Fixed recovery costs and contractual penalty clauses must be added separately.