How to calculate interest and fees correctly
What you may add on top, when interest starts to run — and why most creditors claim too little.
You charge what you are entitled to — interest from the right date, fees on the right letters, and nothing that can be knocked down.
Step by step
- 01
Work out when interest starts to run
If a due date has been agreed, default interest runs from the day after. If nothing has been agreed, it generally starts to run only some time after the claim has been made. That is why a due date in your terms of business is worth money.
- 02
Use the agreed rate of interest — or the statutory one
If a rate of interest has been agreed between two businesses, that rate applies. If it has not, the rate under Renteloven applies. Never put a rate of interest on the invoice that was not agreed in advance — it will not hold.
This is where it goes wrongA rate of interest that first appears on the invoice or in the reminder has not been agreed. It has to be in what the customer accepted when they bought.
- 03
Add the reminder fee — but only three times
100 kr. per reminder, on no more than three reminders per claim, and with at least ten days between each. You may send more letters — but they are free.
- 04
Remember the compensation fee between businesses
If you trade with another business, you can charge a fixed compensation amount on top of the reminder fee when payment is late. It is the item most creditors forget — and it is the one that covers your trouble.
- 05
Add the collection costs when the case moves on
If the collection notice has been sent correctly and the deadline has expired, the collection costs can be imposed on the debtor at the applicable rates. If the notice has NOT been sent correctly, you pay them yourself.
This is where it most often goes wrong
Not because anyone is careless, but because the mistakes are easy to make and only surface once it is too late.
You charge interest you never agreed
It gets knocked down at the first objection, and you have spent time on a calculation that does not hold. The agreement comes first, the interest afterwards.
You put a fee on letters that are not reminders
A courtesy notice sent before the due date is not a reminder. A fee on it is not merely invalid — it weakens your credibility in the whole case.
You forget to claim the interest when the case is closed
If the debtor pays the principal but not the interest, the case is not over. What is left is still a claim — and it does not disappear because it is small.