Interest Calculator
Estimate how your savings or investment grows over time with compound interest. Enter a starting amount, an annual interest rate, a duration, and an optional monthly contribution to see your final balance, total contributions, and total interest earned — updated live as you type.
How it works
Your starting capital and any monthly contributions are compounded every month using an effective monthly rate derived from your chosen annual rate and compounding frequency. This gives an accurate result whether you compound annually, quarterly, monthly, or daily — even when you also add money every month.
Tip
Small, regular contributions can matter more than the starting amount over long periods. Try increasing the duration or the monthly contribution to see how much compounding accelerates growth.
What currency does this use?
None — the calculator works in whatever currency you like. Just be consistent: the result is shown in the same units as your inputs.
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