Your result
How this calculation works
Interest = principal × annual rate ÷ 100 × years. Ending amount = principal + interest.
Calculate the interest on a principal amount using a constant annual rate and a duration in years.
How to use this calculator
- Enter or choose principal.
- Enter or choose annual interest rate (%).
- Enter or choose time (years).
- Select Calculate and review the result and assumptions.
Worked example
At 5% simple annual interest, 10,000 earns 1,500 over three years, for an ending amount of 11,500.
Assumptions and limitations
No compounding, deposits, withdrawals, fees, or tax. Fractional years are accepted.
Frequently asked questions
How is this different from compound interest?
Simple interest is calculated only on the original principal. Compound interest can also earn interest on earlier interest.
Can I enter months?
Divide months by 12 to enter a fractional year, such as 0.5 for six months.