Calculate simple interest earned or owed on a principal amount.
Simple Interest Calculator
Financial
Inputs
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Enter the principal (starting amount).
Enter the annual interest rate.
Enter the time period in years.
Click Calculate.
Simple Interest = Principal × Rate × Time. Unlike compound interest, simple interest is only calculated on the original principal, not on accumulated interest.
Simple interest is calculated only on the principal. Compound interest is calculated on the principal plus accumulated interest, so it grows faster.