How a starting balance and steady contributions grow — and how much of the final number is your money vs. the market's.
Raise your contribution each year, e.g. alongside salary growth.
The S&P 500 has averaged ~10% nominal, ~7% after inflation, over long periods. Compounded monthly here.
This compound interest calculator shows how an initial balance plus steady contributions grow over time, and separates the final number into the money you put in versus the earnings the market added on top. It makes the power of compounding visible.
Earnings are added to your balance and then earn returns themselves. Over long periods this snowball effect means most of your final balance can come from growth, not contributions.
More is always better, but consistency matters most. The calculator lets you test different monthly amounts to see their long-run impact.
A broadly diversified stock portfolio has historically returned around 7% per year after inflation, though future returns are never guaranteed.