Finance Formula • Published on July 30, 2026 • Last updated July 30, 2026
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Simple Interest earned or charged
Principal amount (initial loan or deposit)
Annual interest rate (expressed as a percentage)
Time duration in years
Simple interest is a straightforward method of calculating interest charges on a loan or investment.
Unlike compound interest, simple interest is computed only on the original principal amount.
The interest earned remains constant during each period.
Simple interest is calculated only on the principal amount, so the interest amount is the same every year. Compound interest is calculated on the principal plus accumulated interest, so the interest increases every year.
It is commonly used for short-term loans, automobile loans, and simple retail credit agreements.
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