What interest rate can you charge on a private loan?

The honest answer: a rate close to what an independent lender would charge the same borrower under comparable conditions. That is the market-conform test the Belastingdienst applies, and it protects both sides of the loan.

The band depends on security

A loan secured with a mortgage right on a home sits at the bottom of the band, close to bank mortgage rates. An unsecured consumer loan between family sits higher, closer to personal loan rates. The more risk the lender takes, the higher the acceptable rate.

There is also a hard ceiling: Dutch law caps consumer credit at 14% per year. Anything above that is not just frowned upon, it is not allowed at all.

Too low is also a problem

A rate far below market is not generous in the eyes of the Belastingdienst. The forgone interest counts as a gift, taxed above the yearly exemption of €6,908 for a child in 2026. If you want to be generous, charge a correct rate and gift back within the exemption instead.

Write down why you picked the rate, and review it when conditions change. One line of reasoning in the contract file is enough.

The FLUX5 calculator shows the acceptable band per loan type, based on the Belastingdienst's own guidance. Pick a rate inside the green band and the contract drafts itself around it.