Simple Interest Calculator
Calculate simple interest on your principal investment. See total return, daily interest, and compare with compound interest side by side.
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Simple vs Compound Interest Comparison
| Time | Simple Interest | Compound Interest | Difference |
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How Simple Interest Works
Simple interest is calculated only on the original principal amount. Unlike compound interest, you do not earn interest on previously accumulated interest.
Total Amount = P + SI
Where: P = Principal, R = Annual Rate (%), T = Time (years)
Compound Interest earns interest on both the principal and previously accumulated interest, resulting in exponential growth over time. The difference between simple and compound interest becomes larger with higher rates and longer time periods.
About this Calculator
The Simple Interest Calculator is a free, easy-to-use tool for interest, basic. Simply enter your values and get instant, accurate results — no signup, no ads, no tracking. All calculations run locally in your browser, so your data stays completely private.
Privacy Note: All calculations are performed locally in your browser. No data is ever sent to a server or third party.