CalcArcade.

Interest Rate Calculator

Enter the loan amount, the monthly payment and the term in years. You get the yearly interest rate the payment implies, the total interest and the total paid.

Your numbers

Result

Estimate for information only, not professional advice. Last reviewed .

How we calculate it

A fixed loan payment is M = P × r ÷ (1 − (1 + r)^−n), where P is the amount, r the monthly rate and n the number of months. The calculator solves this for r by repeated halving between 0% and 1,000% a year, then shows r × 12 as the yearly rate.

For example, 300,000 repaid with 1,798.65 a month over 30 years comes out at 6.00%. If the payments add up to exactly the amount borrowed, the rate is 0%.

Assumptions and limits

  • Use the payment of principal and interest only. A payment that includes taxes, insurance or fees gives a rate that is too high.
  • This is the nominal yearly rate compounded monthly. For a rate that includes fees, use the APR calculator.
  • If the payments over the term add up to less than the loan, no rate can fit and the calculator says so.

Frequently asked questions

How do I work out the interest rate on my loan?

Enter the amount you borrowed, the monthly payment and the number of years. The calculator finds the rate at which those payments exactly repay the loan.

Why is the rate higher than my lender quoted?

Your payment may include insurance, taxes or fees, or the term may be different. Only principal and interest should be entered, and fees are covered by the APR calculator.

What if the payment is too low?

If the payments over the whole term add up to less than the amount borrowed, the loan could not be repaid even with no interest. The calculator reports that instead of a rate.

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Worked example (a fixed example using the starting numbers, it does not change as you type)

Inputs: Loan amount = 300000; Monthly payment (principal and interest) = 1798.65; Loan term (years) = 30.

  • Interest rate (APR) 6%
  • Total interest $347,514.00
  • Total paid $647,514.00

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Last reviewed: . Formulas and assumptions are described on our methodology page. For information only; not professional advice.