About the Compound Interest Calculator
Compound interest earns interest on your interest. Enter a starting amount, optional regular deposits, the rate and how often it compounds to see the final balance and a year-by-year table.
Also known as: compound interest formula, compounding calculator, interest on interest, compound savings, compound savings calculator.
How to use this calculator
- Enter principal, monthly deposit, annual interest rate, years and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
A = P(1 + r/k)^(k·t)
- P
- = principal
- r
- = annual rate
- k
- = compounding periods per year
- t
- = years
Worked example
Using the values pre-filled in the calculator above:
- Principal = 10,000
- Monthly deposit = 200
- Annual interest rate = 7 %
- Years = 10
- Compounding: Monthly
the calculator returns:
- Final balance: 54,713.58
- Total deposits: 34,000
- Interest earned: 20,713.58
- Effective annual rate (APY): 7.229%