Compound Interest Calculator
See how savings and investments grow with compound interest and regular contributions.
Future value
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Total contributed
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Total interest earned
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Results update as you type.
About this calculator
Compound interest is interest earned on both your original money and the interest it has already earned. This calculator projects the future value of a starting balance plus optional regular contributions, compounded as often as you choose.
Frequently asked questions
How does compounding frequency matter?
The more often interest compounds, the more you earn, because each new interest payment starts earning interest sooner. The effect is small but real over long periods.
What is the compound interest formula?
A = P(1 + r/n)^(nt) for a lump sum, plus the future value of a series for regular contributions. This tool combines both.
Results are estimates for general guidance only, not financial, medical or tax advice.