Compound Interest Calculator
Project the future value of savings with monthly contributions.
Inputs
Output
Fill in every field to see the future value.
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About Compound Interest Calculator
The Compound Interest Calculator projects how savings grow when interest is earned on both your deposits and the interest already added. Enter a starting amount, a regular monthly contribution, an expected annual rate and a time frame to see the future value.
How to use it
- Enter your starting principal.
- Enter how much you plan to add each month. Use 0 if you will not add anything.
- Enter the expected annual rate of return as a percentage and the number of years.
- Review the future value, the total you contributed, and the interest earned.
Good to know
- Interest is compounded monthly and contributions are added at the end of each month.
- The rate is assumed to stay constant, which real investments rarely do. Try a lower and a higher rate to see a range of outcomes.
- Taxes, fees and inflation are not included, and each of them reduces real growth.
- Results are estimates for planning and comparison. They are not financial advice, and a lender or adviser may calculate figures differently.
Common questions
Why does starting early matter so much?
Growth in each year builds on all the growth before it. Adding ten more years often makes a bigger difference than a larger monthly contribution.
What rate should I enter?
For a savings account, use its advertised rate. For investments, a conservative long-term assumption is safer than a recent good year.