# 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%.