Free Compound Interest Calculator

See how a starting amount plus regular contributions grow over time, with a year-by-year growth chart.

Contribution frequency
Compounding frequency
$144,572.72
Future balance
$48,000.00
Total contributions
$86,572.72
Total interest
PrincipalContributionsInterest
Year 0 → 20 · up to $144,573

How to use / FAQ

Enter a starting amount, an expected annual return, and a time horizon to see how your money could grow. Add a regular monthly or yearly contribution and choose how often interest compounds — the future balance, your total contributions, and the interest earned all update instantly, and the chart shows how the three stack up year by year.

What is compound interest?

Compound interest is interest earned on both your original amount and on the interest already added. Because each period's interest joins the balance and then earns interest itself, growth accelerates over time — which is why starting early matters so much.

How does compounding frequency change the result?

The more often interest is added, the more often it starts earning interest of its own, so daily compounding yields slightly more than yearly at the same rate. The difference is real but usually small compared with the effect of the rate, the contributions, and the number of years.

How are contributions treated?

Your contribution is added regularly over each year and spread across the compounding periods, so it starts earning returns as soon as it's invested. The chart separates your principal, your cumulative contributions, and the interest earned so you can see how much of the final balance is growth versus money you put in.

Is this a guarantee of returns?

No. It's a projection based on a fixed rate you choose. Real investment returns vary year to year and can be negative. Use it to compare scenarios, not as a promise of a specific outcome.