Finance
Simple interest
Calculate interest without compounding and the final balance.
Your numbers
Both a decimal point and a comma work.
Result
150
Interest
- Final amount
- 1,150
How it works
I = P × r × t / 100
Interest equals principal × annual rate / 100 × years. Fractional years are accepted. Accrued interest earns no additional interest; taxes and fees are excluded.
How simple interest works
Simple interest is calculated only on the initial principal: interest = principal × annual interest rate × years ÷ 100. The final balance equals principal plus interest.
Worked example
With principal 1,000, a fixed annual rate of 5%, and a term of 3 years, interest = 1,000 × 5 × 3 ÷ 100 = 150. Final balance = 1,000 + 150 = 1,150.
Assumptions and limitations
This model assumes a constant annual rate, a term expressed in years and no compounding. It does not account for fees, taxes, inflation, intermediate payments or changing rates. For interest on accumulated interest, use the compound-interest calculator.