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Simple Interest Calculator

Calculate interest earned or owed using the simple (non-compounding) interest formula.

Simple interest formula

Simple interest is calculated only on the original principal, using the formula I = P × r × t, where P is the principal, r is the annual interest rate and t is the time in years. Unlike compound interest, previously earned interest doesn't itself earn more interest, which makes this the formula typically used for short-term loans, certain bonds and some promotional financing.