Investment Calculator
Project how your investments can grow over time.
All calculations happen locally in your browser — nothing is uploaded, stored or tracked.
Enter your starting amount
Current portfolio value.
Add contributions
Monthly or annual.
Set return and years
See nominal and real growth.
What Is an Investment Calculator?
An investment calculator projects the future value of an investment portfolio given an initial amount, regular contributions and an assumed annual return. It shows the growth from contributions separately from the growth from returns.
An optional inflation adjustment converts the future value into today's purchasing power, which is the number that matters for real goals.
The Formula
P is the initial investment, C the annual contribution, r the annual return, n the years. Returns are assumed to compound annually.
Your data never leaves your device.
Every calculation on this site runs in your browser using vanilla JavaScript. Nothing is uploaded, stored or tracked.
- 100% local, client-side calculations
- No data stored on any server
- No tracking, no analytics, no ads scripts
- Works offline once loaded
Frequently Asked Questions
How do investments grow?
Through returns — dividends and price appreciation — which compound when reinvested. Time is the most powerful factor.
What return should I assume?
Historically, diversified stock portfolios have averaged roughly 7–10% nominal over long periods, but past performance is no guarantee.
Does the calculator include taxes?
No — returns are pre-tax. Tax treatment varies by account type and jurisdiction.
What is the difference between nominal and real return?
Nominal is the headline percentage; real subtracts inflation, showing the actual gain in purchasing power.
Is this financial advice?
No — it is a math projection based on your assumptions.