Calculate an annual interest rate

Enter the loan principal, payment amount, and duration to calculate the corresponding annual interest rate.

Guide to using this form

• By default, the calculation is performed for monthly payments and a simple interest rate. To change these settings, select the “Advanced entry” box. Note that this feature requires that JavaScript be enabled in your brower.

• This calculation will display the interest rate that would give the exact payment amount entered, or if that is not possible, the rates that would give the closest possible payment amount. The interest rate is bounded between 0% and 30%.