FINANCE · FREE TOOL
Implied loan interest-rate calculator
Solve the nominal interest rate implied by fixed monthly loan payments.
Your inputs
Enter your values, then calculate.
Decimal-point numbers; displayed rounding does not change internal values. Calculations stay on this device.
YOUR RESULT
Make the numbers clear.
Save calculation JSON ↓Calculation breakdown
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How this calculation works
Numerically solve the installment-payment equation between0% and100% nominal annual interest. Also show the effective annual rate from monthly compounding. Payments imply no fees; neither result is a disclosed regulatory APR.
Reference: method and limitations. Method reviewed October 22, 2026.
Check the assumptions
Use one currency consistently; financial outputs use that same currency, except the U.S. tax tool specifically uses USD. Financial models use your assumptions, not live rates or personalized financial advice. Check the result against your contract or the applicable tax rules.