Plain Finance Tools · Free calculator
See the math behind your money.
Estimate how a starting amount and regular deposits could change over time. Separate the money you put in from the interest in the projection, then check the result year by year.
Open the compound interest calculatorOne tool, with the assumptions in view
Change the rate, time horizon, deposit schedule, and compounding frequency. The calculator runs in your browser. You can see the formula and a worked example before relying on a result.
The projection uses a fixed rate and leaves out fees, taxes, inflation, and changing returns. It is a way to explore a scenario, not a promise about what an account or investment will earn.