Financial Calculators
Interest Rate Calculator
Work out the interest rate on a loan.
FreeNo sign-upWorks in your browser
Enter details
$
$
Result
Estimated interest rate (APR)
7.42%
Total interest
$4,000.00
About the Interest Rate Calculator
Know the payment but not the rate? Enter the loan amount, the monthly payment, and the number of payments and the calculator solves for the implied annual interest rate (APR) and the total interest. It's perfect for reverse-engineering a quoted deal or checking whether a loan offer is fair.
How to use the Interest Rate Calculator
- 1Enter your loan amount, monthly payment, and number of payments.
- 2Read the result instantly — it recalculates as you type.
- 3Adjust the numbers to model different scenarios.
Frequently asked questions
How do I find the interest rate on a loan?
From the amount, payment, and term, the rate is found by solving the amortization equation numerically — which this tool does instantly.
Why is my rate higher than advertised?
Fees and points raise the effective rate. The APR Calculator factors those in for the true cost of borrowing.