financial calculators
By Quantor Team
April 5, 2024
4 min read

Solve for the Rate: Interest Rate Calculator

Find the implied interest rate of a loan or investment based on payments and principal.

Solve for the Rate: Interest Rate Calculator

Sometimes you know the original loan amount, duration, and the monthly payment, but you do not know the actual interest rate being charged. This is common when dealers offer "special financing."

Finding the Hidden Rate

Because the mathematical formulas surrounding annuities and loans cannot be arranged to directly isolate the rate (r), determining the interest rate usually requires iterative numerical solving methods.

Our automated Interest Rate Calculator handles these complex iterative algorithms instantly, giving you the true APR of your loan.