Compound Interest Calculator

See how your money grows over time with the power of compound interest

Investment Details

Initial Investment ($)

Monthly Contribution ($)

Length of Time (years)

Estimated Interest Rate (% annual)

Interest Rate Variance (%)

Compound Frequency

Total Contributions

Total Interest Earned

Future Value

Year	Starting Balance	Contributions	Interest	Ending Balance

Fixed return rate — A constant annual return is assumed. Actual market returns vary year to year.

Monthly contributions — Contributions are added at the end of each month. Actual timing may vary.

No fees or taxes — Investment fees, expense ratios, and taxes on gains are not modeled.

No inflation adjustment — All values are nominal. Real purchasing power will be lower.

Variance is symmetric — The variance band assumes equal probability above and below the base rate.