Investment Calculator
See what regular investing could grow to: enter a starting amount, a monthly contribution and an expected average return, and optionally view the result in today's money after inflation.
Runs in your browser
How to use
- Enter your starting amount and monthly contribution.
- Enter an expected average annual return.
- Choose the number of years and optional inflation.
- Read the projected value and growth.
How it works
Contributions are added monthly and the portfolio grows at a constant effective annual return. The inflation-adjusted value divides the result by (1 + inflation)^years to express it in today's purchasing power.
Real investment returns vary from year to year and can be negative. A constant rate is a planning assumption, not a forecast.
Examples
- 20-year plan
- 5,000 + 300 a month at 6% for 20 years → about 152,067 (77,000 invested); about 102,337 in today's money at 2% inflation.
Common uses
- Retirement and long-term planning
- Comparing contribution levels
- Understanding the effect of time and returns
Privacy & security
This tool runs entirely in your browser. Your files and text are never uploaded to our servers — processing happens on your device and results are created locally. How each tool handles files
Frequently asked questions
What return should I assume?
Use conservative figures and test several scenarios. Historical averages depend heavily on the asset mix and period.
Are fees included?
No. Subtract fund fees from the expected return (e.g. 6% − 0.5% fees = 5.5%).
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