Lending Calculator
Lend money to someone and know exactly what they pay back each month. Simple flat interest — total divided by months.
This calculator uses simple interest: the total interest is calculated upfront, added to the principal, and divided equally across all months. No compound interest, no changing payments — just one fixed amount per month.
Lending money to friends or family
When you lend money to someone you know, clarity prevents problems. Before handing over any amount, agree on the total, the interest (if any), the monthly payment, and the timeline. Write it down — even a simple message or email counts. This protects both sides and keeps the relationship healthy.
This calculator uses simple (flat) interest rather than the compound interest banks use. The difference: with flat interest, you calculate the total interest upfront and spread it equally. With compound interest, interest is charged on the remaining balance each month, so early payments are mostly interest. For informal lending, flat interest is far easier to understand and communicate.
You are not required to charge interest. Many people lend to family at 0% — that is perfectly fine. If you do charge interest, keep it reasonable. In most European countries, charging excessive interest (usury) is illegal. A rate between 1% and 5% per year is common for private lending. Above that, you should have a good reason.
In the Netherlands and many EU countries, private loans above a certain threshold should be reported to tax authorities — the lender declares it as an asset (box 3 in the Netherlands), and the borrower may deduct it. Consult a tax advisor for larger amounts.