How your money grows over time — with monthly contributions and compounding.
Compound interest means you earn returns not just on your original deposit but on the returns it has already generated — interest on interest. Over a few years the effect is modest; over decades it dominates, which is why time in the market matters more than timing it. This calculator compounds monthly and adds your contribution each month, then splits the result into what you put in versus what the growth added. Two things drive the outcome more than people expect: the number of years (the curve steepens the longer it runs) and the regular monthly contribution, which often ends up contributing more to the final balance than the starting lump sum. It's an estimate with a fixed rate — real returns vary and ignore tax and inflation. To compare the cost of borrowing instead, see the loan calculator.