Any debtor who is late in paying should know: the legal interest rate is the amount that a debtor must pay to his creditor (the person to whom the money is owed) when the debt is not paid on time. Set every six months by the State, it aims to compensate the creditor for the damage suffered. As of January 1, 2026, it has changed slightly. And the rate is far from negligible: each day of delay can increase the bill.
Since 2015, remember that two distinct rates exist: one for debts between individuals, the other when the creditor is a professional (artisan, bank, company, etc.).
Rates applicable to the first half of 2026
Between January 1 and June 30, 2026, the legal interest rate applicable to debts between individuals was set at 6.67% annually per decree of December 15. It progresses very slightly compared to the second half of 2025 (6.65%), but remains below the high levels of recent years when it exceeded 7%, even 8%.
This rate concerns, for example, a parent who pays alimony late, an ex-spouse who delays paying alimony compensatory benefit after a divorce, an owner ordered to return a security deposit to his former tenant, or a loved one who does not honor his acknowledgment of debt. In all these situations, each day of delay produces interest calculated at the legal rate.
If you owe money to a professional, the rate is lower. It falls to 2.62% for the first half of 2026, compared to 2.76% in the second half of 2025 and 3.71% in the first half of 2025. It applies for example to an unpaid invoice to a craftsman, but also sometimes when an individual is late in paying a consumer loan.
How to calculate late payment interest?
Even if the rate is expressed as an annual percentage, the interest is calculated to the nearest day. The formula is as follows: amount due × number of days late × rate / (365 × 100).
Let’s take a concrete case. An individual owes you 5,000 euros after a court decision and pays you 40 days late in the first half of 2026. You can claim 36.54 euros in late payment interest (5,000 × 40 × 6.67 / 365 x 100).
Another example: you are 60 days late in paying an invoice for 10,000 euros to your house builder. The interest is a little lower than for individuals but, in our example, it amounts to around 43 euros (10,000 × 60 × 2.62 / 365 x 100).
But the bill can quickly mount up if the delay continues. Two months after the application of a judgment, the legal interest ratel is increased by 5 points: for a debt between individuals, it is then close to 12%! On alimony unpaid for several months or on compensation of several thousand euros, the additional cost becomes significant.
In certain cases, the judge can also decide on the capitalization of interest. These are then added to the capital and themselves produce interest each year, a snowball effect which increases the debt.
In 2026, with an annual rate above 6%, it is therefore better to avoid leaving an arrears payment, especially if the delay lasts or if the sums involved are significant.
