About the Interest Rate Calculator
Find the interest rate of a loan when you know the amount, the monthly payment and the term. This tool is free, works in your browser and needs no sign-up.
How to use the Interest Rate Calculator
Enter the loan amount, the monthly payment and the number of months. The tool works out the yearly rate for you.
Formula used
The tool solves Payment = P × r × (1 + r)^n ÷ ((1 + r)^n − 1) for r by repeated halving.
Example
With Loan amount 10000, Monthly payment 313.36, Loan term (months) 36, the calculator shows: Interest rate = 7.999% per year; Monthly rate = 0.6666%; Total interest = 1,280.96.
Frequently asked questions
Is the Interest Rate Calculator free to use?
Yes. It is completely free and you can use it as many times as you like.
How accurate is the Interest Rate Calculator?
The calculator uses standard formulas, so the maths is exact. Real life results can differ because of fees, taxes, rounding or personal factors, so treat the answer as an estimate.
Do you store the numbers I enter?
No. All calculations run in your browser. The values you type are not sent to our server.
Disclaimer: results are estimates for information only. They are not financial, medical or professional advice.