Stock Investment Calculator — initial investment, contributions, return & future value.
Stock Investment Calculator
Project how an initial investment and recurring monthly contributions can grow over time with compound returns.
Investment inputs
Portfolio projection
How compounding works
Investment growth compounds when returns are earned on both the original amount and the accumulated gains. The longer the time horizon, the more significant the effect of compounding can become.
This tool estimates the future value of a stock portfolio using an initial lump sum and recurring monthly additions. It assumes a consistent annual return and monthly compounding.
Although stock performance varies, the model is useful for understanding how regular investing and time can build wealth over the long term.
- Higher annual returns increase future value.
- Longer holding periods amplify compounding.
- Monthly contributions add meaningful momentum.
- Consistency often matters more than timing.
Frequently asked questions
What return rate should I use?
A reasonable estimate depends on your asset mix, risk level, and time horizon. Many long-term planners use historical average stock market ranges as a rough guide.
Does this include taxes or fees?
No. This estimate focuses on growth before taxes, trading costs, or account fees.
Are monthly contributions added at the start or end of the month?
This estimate assumes contributions are made at the end of each month, which is the most common planning assumption.
Is this a guaranteed forecast?
No. It is a model for educational planning and not a promise or guarantee of future market performance.