Compound Interest Calculator

Project a balance from principal, a fixed interest rate and a compounding schedule.

Your calculation

%
years
Result

Projected balance

$1,647.01

Interest earned
$647.01

Fixed nonnegative rate, no contributions, fees, taxes or inflation. A mathematical projection, not a guaranteed return.

Calculated in your browser. Your inputs are not sent to a server.

How to use this calculator

Enter a starting balance, nominal annual rate, duration in years and compounding frequency. The result separates your principal from projected interest.

The math behind it

Final balance = principal × (1 + annual rate ÷ 100 ÷ periods per year)^(periods per year × years)
Interest = final balance − principal

A worked example

1,000 at a nominal annual rate of 5%, compounded monthly for 10 years, grows to about 1,647.01, including 647.01 interest.

Assumptions & precision

Fixed nonnegative nominal rate. No additional contributions, withdrawals, taxes, fees, inflation or investment risk. Daily means 365 periods per year. Fractional years use fractional exponents, a mathematical interpolation that may differ from actual crediting dates. This is not an APY input or guaranteed investment return. Currency changes display only; no exchange-rate conversion. Money is rounded only for display using the currency’s fractional digits. Results above 10¹⁵ are rejected.

A common question

Is this the same as annual percentage yield?

No. This input is a nominal annual rate divided across compounding periods. APY already accounts for compounding and should not be entered as the nominal rate without conversion.