Compound Interest Calculator

Estimate future balance, total contributions, and interest growth from principal, monthly deposits, rate, and time.

What this calculator estimates

Compound interest shows how an initial balance, recurring deposits, rate of return, and time can work together. The calculator separates contributions from estimated growth so you can see how much comes from saving versus compounding.

How to use the result

Try different monthly contributions, rates, and time horizons. A longer timeline can matter more than a small rate change, but the estimate should not be treated as a guaranteed return.

Important limitations

Real investments can go down, rates change, inflation reduces purchasing power, and taxes or fees can reduce the ending balance. Use this as a planning tool, not financial advice.

Practical planning tip

Compare a conservative rate with an optimistic rate. If a plan only works with a very high return, it may be too fragile for real-world budgeting.

How to use it

Enter the starting amount, monthly contribution, annual rate, and number of years.
Review future value, contributions, and estimated interest.
Run at least two scenarios before using the estimate in a savings plan.

Frequently asked questions

Does this predict investment returns?

No. It estimates growth from the numbers you enter and does not predict market performance.

Are taxes and fees included?

No. Subtract expected taxes, account fees, or fund expenses separately for a more conservative estimate.

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