See how your money grows with compound interest and optional monthly contributions. Enter an initial deposit, contribution amount, interest rate, and time horizon, then view your ending balance, interest earned, year-by-year schedule, and chart.
Note: This tool uses a constant annual rate for illustration. Real investments (stocks, ETFs, dividends) vary. For dividend income estimates, try our dividend calculator. For bond yield math, try our yield to maturity calculator. For historical returns on real tickers with DRIP, use our Stock Return Calculator.
| Year | End balance | Total contributed | Interest earned |
|---|
Model actual tickers with dividends, splits, and periodic investments — not just a fixed rate.
Compound interest means you earn interest on your balance and on interest already earned. Over long horizons, that snowball effect dominates growth, especially when you add regular contributions.
The future value with monthly contributions (end of month) is often written as:
FV = P(1 + r/n)nt + PMT × [((1 + r/n)nt − 1) / (r/n)]
Where P is initial principal, PMT is the periodic contribution, r is the annual rate, n is compounding periods per year, and t is years.