The rates were last updated and checked against the sources on 16 Oct 2026. This is an indicative calculation — if in doubt, the official rates and rules apply.
About the Late Payment Interest Calculator
Late payment interest (forsinkelsesrente, also called morarente) is the interest a creditor can charge when a money claim isn't paid by its due date. The right to claim it follows from the Norwegian Act relating to interest on overdue payments (forsinkelsesrenteloven) and requires no agreement: interest runs from the day after the due date until payment, whether or not the invoice mentions it. If no due date was agreed, interest runs from 30 days after the creditor sent a written demand for payment.
The rate is set every six months by Finanstilsynet, with effect from 1 January and 1 July, and must equal Norges Bank's policy rate plus at least 8 percentage points. The authority was delegated from the Ministry of Finance in June 2025. Because the rate changes twice a year, a claim that has gone unpaid for a while almost always spans several rate periods — and each period has to be calculated separately. This calculator splits the period automatically and shows every step, so you can check the arithmetic.
On top of the interest, the creditor can claim a standard compensation for collection costs under § 3a — a fixed amount set at the same time as the rate and equal to 40 euros converted to Norwegian kroner. It can only be claimed when the debtor is a business, a public authority or another legal entity. It does not apply to consumers, and when the debtor is a consumer it is also not permitted to agree on a higher late payment interest rate than the one Finanstilsynet has set.
How to use the calculator
1
Enter the principal
The amount that was unpaid on the due date, without interest, reminder fees or debt collection fees. If you have several overdue invoices, calculate each one separately — they have different due dates.
2
Set the due date and payment date
The due date is the last day the claim could be paid on time. If the claim is still unpaid, set the payment date to today to see what the interest is now.
3
Choose whether to include standard compensation
Include it when the debtor is a company or a public body. Leave it out when the debtor is a private individual.
4
Add partial payments or an agreed rate, if any
If the debtor has paid part of the claim, add each payment with its date — interest then runs on what's left. If your contract sets its own late-payment rate, switch to Agreed rate.
5
Check the breakdown
The table shows the days, rate and day basis for each rate period. If the rows add up, the total adds up — and you can show the calculation in a payment reminder or a claim to the conciliation board (forliksrådet).
Frequently asked questions
When can I charge late payment interest?
From the day after the due date, as soon as a money claim isn't paid on time. The right follows directly from forsinkelsesrenteloven and needs no agreement or notice — it's enough that payment is late. If no due date was agreed, interest runs from 30 days after you sent a written demand for payment. If the delay is caused by something on the creditor's side, the interest may lapse.
What is the late payment interest rate now?
12.25% a year for the period 1 Jul 2026–31 Dec 2026. The rate is set every six months by Finanstilsynet, with effect from 1 January and 1 July, and must be Norges Bank's policy rate plus at least 8 percentage points. The standard compensation in the same period is NOK 430.
Why is the calculation split into several periods?
Because the rate changes on 1 January and 1 July. A claim that fell due in March last year and is paid in October this year has run through several different rates, and each part of the period has to be calculated at the rate that applied then. The calculator therefore splits at every half-year change — and at every year end, because the number of days in the year (365 or 366) is the divisor.
Which day count is used?
Actual calendar days / 365 (366 in leap years). The Act doesn't itself prescribe a day count, so the calculator follows the same method as Finanstilsynet's own calculator: interest is calculated per calendar day, from the day after the due date up to and including the payment date, and each day is divided by the number of days in its own year. In a leap year the divisor is 366, so the leap day doesn't add a day's extra interest.
What is the standard compensation for collection costs?
A fixed amount the creditor can claim on top of the interest when a claim isn't paid by its due date, under forsinkelsesrenteloven § 3a. It equals 40 euros converted to Norwegian kroner and is set every six months together with the rate — so it can go down as well as up. It is NOK 430 from 1 Jul 2026. The compensation can only be claimed from businesses, public authorities and other legal entities, never from a consumer.
Can I agree on a higher rate than the official one?
As a starting point, the parties are free to agree on a different late payment interest rate, higher or lower — choose Agreed rate above to calculate with it. But if the debtor is a consumer, a higher rate than the one Finanstilsynet has set cannot be agreed — see § 4 (c) of the Act. And if interest was already running under the contract before the due date, the creditor may keep charging that rate instead (§ 3, second paragraph). Questions about the rules themselves fall under the Ministry of Justice and Public Security.
How are partial payments handled?
Add each payment with its date and amount. Interest runs on the full principal up to and including the day of a payment, and on the reduced principal after it — it is never charged on unpaid interest. The law doesn't decide what a payment covers first: a debtor who pays voluntarily may say, otherwise the creditor decides, and creditors usually take costs and interest first. That is the default here; you can switch to principal first. The standard compensation counts as a cost.
Why does the calculator say some days aren't included?
Because the rate for that period hasn't been set yet. Rates are known up to and including 31 Dec 2026; interest for days after that can't be calculated by anyone until Finanstilsynet publishes the next rate, normally at the end of June and the end of December. We show how many days are affected instead of guessing at a rate or silently skipping the days.
Are the amount and dates I enter stored?
No. The whole calculation happens in your browser, and neither the amount, the dates nor the result is sent to a server or stored anywhere. You can safely calculate on a real customer claim here.