Compounding pays interest on interest. Enter a starting amount, rate and years — the future value updates instantly, with monthly compounding as the default.
with n compounding periods per year. With yearly deposits the calculator iterates the balance period by period, adding each deposit before it starts earning.
Frequently asked questions
What is the Rule of 72?
Divide 72 by the annual rate to estimate the doubling time: at 6% money doubles roughly every 12 years. The stat cards show this next to the exact result.
Monthly vs annual compounding — which is better?
More frequent compounding yields more: monthly beats annual at the same nominal rate, because interest starts earning interest sooner.
Is compound interest guaranteed?
The math is exact, but the rate itself is not: savings accounts float, and investments can lose value. Treat the output as arithmetic on your assumptions, not a forecast.