Simple Interest Calculator
Calculate interest using the simple interest formula I = P × r × t. Shows total interest earned and final amount.
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Total Amount
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Interest Earned$0
Principal$0
📐 Formula
I = P × r × t, where I = interest, P = principal, r = annual rate (decimal), t = time in years
Frequently Asked Questions
Simple interest is calculated only on the principal. Compound interest is calculated on the principal plus accumulated interest. Over long periods, compound interest grows significantly faster.
Simple interest is used for short-term loans like car loans, personal loans, and some mortgages. Banks typically use compound interest for savings accounts and long-term investments.
For monthly simple interest, use the formula I = P × (r/12) × t where t is the number of months. Or just use r/12 as your monthly rate.