Compound Interest Calculator
See how savings grow with compounding — monthly contributions, totals and a full schedule.
Free · No sign-up · Runs locally in your browser · Also available in Chinese (中文)
What is Compound Interest Calculator?
A compound interest calculator projects the future value of money that earns interest on interest. You enter a starting amount, a rate, a term and optional recurring contributions; the tool applies the compound formula period by period and returns the final balance plus the total interest earned.
Compounding is why starting early beats starting big: contributions made in year one compound for the entire term. The schedule view makes this visible — the interest column grows faster each period while the principal column stays flat, which is the whole strategy of long-term investing in one table.
How to use it
- 1Enter the initial deposit and, if applicable, the monthly contribution.
- 2Set the annual rate and the term in years.
- 3Choose the compounding frequency (monthly or annually).
- 4Read the final balance, total interest and the period-by-period schedule.
Common use cases
- Comparing savings accounts or fixed deposits with different rates and terms.
- Motivating an early start by seeing how ten extra years multiplies the outcome.
- Planning a down-payment fund with a fixed monthly contribution.
Frequently asked questions
▸Does compounding frequency matter much?
At the same nominal rate, monthly compounding yields slightly more than annual. The difference grows with the rate — at 8% over 20 years it is a few percent of the final balance.
▸Are taxes and inflation included?
No — the result is nominal. For a rough real-terms view, subtract expected inflation from the rate before entering it.