Compound interest is what makes long-term investing powerful: your returns start earning their own returns. Enter a starting amount, a regular monthly contribution, an expected annual rate, and a time horizon to see how your investment could grow.
How It’s Calculated
This calculator assumes monthly compounding: your expected annual return is divided by 12, and your monthly contribution is added at the end of each month. Future Value = Principal × (1 + r)^n + Monthly Contribution × (((1 + r)^n − 1) ÷ r), where r is the monthly rate and n is the number of months.
A Note on Assumptions
This tool projects a constant annual return, which real markets never deliver — actual returns vary year to year. Treat the result as a rough, useful estimate for planning rather than a guarantee, and remember that inflation and taxes aren’t factored in here.