Interest Rate Calculator

Estimate the annual rate implied by a loan amount, payment, and term.

Interest Rate Calculator helps you estimate the annual rate implied by a loan amount, payment, and term. Enter loan amount, monthly payment, and term, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Interest Rate calculator does Interest Rate Calculator is built for money decisions — loans, savings, payments, and taxes. Estimate the annual rate implied by a loan amount, payment, and term. You enter loan amount, monthly payment, and term, then Simple Calculators computes the result instantly. Rates, fees, and tax rules vary by lender and country, so treat results as planning numbers, not a contract. How the math works Enter the Loan amount, Monthly payment and Term in months. The calculator tries rate after rate until the standard loan payment formula, payment = amount × r × (1 + r)^months ÷ ((1 + r)^months − 1), gives your payment; r is the monthly rate. The annual rate shown is r × 12. It assumes fixed equal monthly payments and does not separate out fees paid up front. The formula: Find r so that M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1); annual rate = r × 12. M is the monthly payment, P the loan amount, n the nu…