How to use this tool
Enter the starting balance, monthly investment and assumed effective annual return.
Choose the number of years and contribution timing. A constant return illustrates compounding, not a promised investment outcome.
Balance = P(1+r)^n + C[(1+r)^n−1]/r
Worked example
$47,161.58 · projected balance
Fixed example using the settings below. Monetary examples use USD; dates and times use their stated reference values. This example stays unchanged when you edit your calculation.
Example inputs
- Starting balance: 10000
- Monthly contribution: 200
- Assumed effective annual return (%): 5
- Whole years: 10
- Contribute: End of month
Method illustration: Investing 100 per month for one year with zero return produces 1,200.
Assumptions and limits
- Assumed rates remain constant. Values are estimates before tax and fees unless entered explicitly. No return or affordability is guaranteed.
- Calculations use full precision; displayed money is rounded to cents.
Method reference: Investor.gov saving and investing tools
Check or report a result
Check the units, selected calculation and assumptions first. Compare the fixed example above with your inputs to identify what changed.
Report a calculation issue with the page address, hypothetical inputs, result displayed and result expected. Do not include passwords, bank details or other private information.