Savings Compound Interest Calculator
See how a savings account grows with regular deposits and compounding.
Inputs
How it works
The future value formula is FV = P(1+r/n)^(n·t) plus the future value of an annuity for ongoing contributions. We compute month-by-month so the contribution growth is exact.
Frequently asked questions
How does compound interest work?
Compound interest pays you interest on both your original deposit and the interest you've already earned. The longer the money stays invested, the more this effect snowballs.
What does 'compounding frequency' mean?
It's how often interest is added to the balance. More frequent compounding (daily vs. annually) produces slightly higher returns at the same stated rate.
Should I include inflation?
If you want real purchasing power, use a return rate that is your expected return minus inflation (e.g. 7% nominal minus 3% inflation = 4% real).
What's a realistic stock-market return?
Long-run U.S. stock returns have averaged about 7%-10% before inflation, but any given decade can be very different.
Are these results guaranteed?
No. Past returns don't guarantee the future. Treat the result as a projection, not a promise.