Compound interest calculator
See how your money grows with compound interest. Enter an initial amount, optional monthly or yearly contributions, your rate, and how often interest compounds, then view the future value, total interest, and a year by year schedule. Everything runs locally in your browser.
How this compound interest calculator works
- Enter your initial investment and any regular contribution. Use a negative contribution to model withdrawals.
- Set the interest rate, the number of years, and how often interest compounds, from yearly up to daily or continuous.
- The calculator applies the formula
A = P(1 + r/n)^ntand adds the growth of your contributions period by period. - Review the future value, total interest, effective yield, and the full year by year growth schedule.
Example: 5,000 dollars at 5% compounded monthly grows to around 5,256 dollars after one year, before any contributions.
Compound interest calculator FAQ
What is compound interest?
Compound interest is the interest you earn on both your original money and the interest it has already earned, so your balance grows faster over time.
How do I calculate compound interest?
If you deposit 5,000 dollars at a 5% annual rate compounded monthly, your ending balance would be about 5,255 dollars after one year.
Does compounding frequency matter?
Compounding more often means interest is added more frequently, so daily compounding earns a little more than monthly or yearly compounding at the same rate.
How long until my money doubles?
To estimate growth quickly, the Rule of 72 estimates how long it takes to double your money by dividing 72 by the interest rate.
What is continuous compounding?
For the smoothest growth, continuous compounding uses the formula A equals P times e to the power of r t.