Interest Rate Calculator

Work out the APR hidden in a loan offer from the loan amount, monthly payment and term.

How this calculator works

The rate is found by searching for the monthly rate at which the standard loan payment formula matches your payment.

Frequently asked questions

Why is my real APR higher than the quoted rate?

Fees and add-on costs raise the effective rate, which is what this calculator reveals.

Figures use 2026 US federal tax parameters. Results are estimates only.