Investment Growth Calculator
Project how an initial investment plus regular monthly contributions grows over time with compound returns.
Projected future value
$144,573
Total contributed
$58,000
Interest earned
$86,573
Recommended Settings
Pro Tips
- •Contributions are assumed to happen monthly and compound at the same monthly rate as your investment returns
- •The earlier you start, the more time compounding has to work - extending the time horizon often matters more than increasing the monthly contribution
- •This uses a fixed, steady annual return for simplicity - real markets fluctuate year to year, so treat the result as a long-run estimate, not a guarantee
- •Compare a couple of scenarios with different monthly contributions side by side to see how much extra saving actually moves the outcome
Most Popular
Many people model a 7% annual return, a commonly cited long-run average for a diversified stock portfolio
When to Use This Tool
Project how a retirement or brokerage account grows with steady monthly contributions.
See how increasing your monthly contribution changes your long-term outcome.
Understand how much of your final balance comes from contributions versus compound interest.
Estimate how many years it takes to reach a specific investment goal.
How It Works
Convert your annual return rate into a monthly compounding rate
Grow your initial investment forward using standard compound interest over the full time horizon
Add the future value of your monthly contributions using the standard future-value-of-an-annuity formula, then combine both totals
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Frequently Asked Questions
Does this account for fees or taxes?
No, this projects gross growth based only on your inputs. Real-world fees, taxes, and account-specific rules will reduce actual returns, so treat this as an upper-bound estimate.
Why does the interest earned exceed my contributions after many years?
This is the effect of compound growth - especially over long time horizons and higher return rates, the returns earned on both your initial investment and your growing balance of prior contributions can eventually exceed the money you put in yourself.
What return rate should I use?
There's no universally correct number - many long-term planning tools use a range around 5-8% for a diversified stock portfolio, but you should choose an assumption consistent with your own investment strategy and risk tolerance.
Is this financial advice?
No, this is a general-purpose projection tool based on your own assumptions, not personalized financial advice. Consult a financial advisor for guidance specific to your situation.
Is my financial data sent anywhere?
No. All calculations happen locally in your browser.