Compound Interest Calculator
See how an investment grows when interest earns interest. Add an initial amount and regular monthly contributions and watch the future value update instantly.
How it works
- 1
Enter your starting amount
What you invest today — it can be zero.
- 2
Add contributions and rate
Monthly deposits, annual return and how often interest compounds.
- 3
See the future value
Total contributed, interest earned and the final balance.
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Frequently asked questions
More frequent compounding (monthly instead of yearly) produces a slightly higher balance for the same annual rate.
Why compound interest matters
With compound interest, the returns you earn are added to the balance and start earning returns themselves. Early on the effect is small, but over decades it can make interest the largest part of your savings.
Time matters more than almost anything else. Starting ten years earlier often beats contributing twice as much later, which is why the calculator is useful for retirement and long-term goals.
Real returns vary, and inflation, taxes and fees reduce them. Use the result to compare scenarios, not as a guarantee. This is not financial advice.