Free calculator

Compound Interest Calculator

Free Compound Interest Calculator with instant browser-based results and a clear calculation breakdown.

💰 Compound Interest Calculator

Calculate how your investment grows over time with compound interest. Enter your initial amount, contribution details, interest rate, and time period to see your potential returns.

Initial Principal Amount ($)

Please enter a valid principal amount (0 or greater)

Regular Contribution ($)

Please enter a valid contribution amount (0 or greater)

Contribution Frequency

Annual Interest Rate (%)

Please enter a valid interest rate (0-100%)

Time Period (Years)

Please enter a valid time period (greater than 0)

Compounding Frequency

Final Balance

$0.00

Total Contributions: $0.00

Total Interest Earned: $0.00

Initial Principal: $0.00

Regular Contributions: $0.00

How it works: Compound interest is calculated using the formula: A = P(1 + r/n)^(nt) for the principal, plus the future value of an annuity for regular contributions: PMT × [((1 + r/n)^(nt) - 1) / (r/n)]. Where P is principal, r is annual rate, n is compounding frequency, t is time in years, and PMT is the regular contribution amount.

Want to understand the calculation?

See examples, formula notes and limitations.

Read the guide