Simple Interest Calculator
Calculate simple interest (SI = P*R*T/100) with 3 solver modes, partial years, and 10+ extras including comparison with compound interest. 100% private.
About Simple Interest Calculator
Calculate simple interest (SI = P*R*T/100) with 3 solver modes, partial years, and 10+ extras including comparison with compound interest. 100% private. Everything runs locally in your browser — your data never leaves your device.
How to use
- Enter your input in the tool above.
- Adjust any options to your preference.
- Use the Copy or Download buttons to save the result.
- Everything happens locally — your data never leaves your browser.
FAQ
What is the simple interest formula?
Simple Interest (SI) = Principal × Rate × Time / 100. Total Amount = Principal + SI. Unlike compound interest, SI accrues only on the original principal.
What extras does this tool have?
Extras: (1) Solve for SI given P,R,T, (2) Solve for P given SI,R,T, (3) Solve for R given P,SI,T, (4) Solve for T given P,SI,R, (5) Partial years (e.g. 2.5 years), (6) Compare side-by-side with compound interest, (7) Monthly interest breakdown, (8) Yearly interest breakdown, (9) CSV export of breakdown, (10) Multi-currency, (11) Copy individual results, (12) Per-day interest calculator, (13) Inflation-adjusted future value estimate.
Related tools
Area Converter
Convert between m², km², ft², acre, hectare, mi² with all-units table. 100% private. 100% private.
Binary Calculator
Add, subtract, multiply, divide binary numbers with step-by-step solution. 100% private. 100% private.
BMI Calculator
Calculate Body Mass Index (BMI) from height and weight in metric or imperial units. Get category (underweight / normal / overweight / obese), healthy weight range, and 10+ extras. 100% private.