Investment Calculator
Calculate investment returns, compound growth, and portfolio performance.
Investment Details
Advanced Settings
Future Value
After 20 years
Total Contributions
Money you invest
Total Earnings
Investment growth
Real Value
Inflation adjusted
After Tax
20% on gains
Investment Summary
Projected Growth
Indigo = investment growth, gray = money you contributed.
Where the Money Comes From
Investment Tips
- • Start investing early to maximize compound growth
- • Consistent monthly contributions create steady wealth building
- • Diversify across different asset classes and markets
- • Keep fees low to maximize your returns
- • Stay invested through market ups and downs
How it works
An investment calculator projects how an initial amount plus regular contributions grow at a compounding rate of return. The starting sum compounds on its own, while each contribution becomes its own compounding stream — together they form the future value. Small changes in rate or time horizon produce large differences at the end because growth is exponential.
Future value with contributions
FV = PV(1 + r)ⁿ + PMT · [(1 + r)ⁿ − 1] / r
- FV
- future value (ending balance)
- PV
- present value (initial investment)
- PMT
- contribution each period
- r
- return per period
- n
- number of periods
Worked example
- Initial PV = $10,000
- Contribution = $500/month at 7% annual (~0.583%/month)
- Horizon = 20 years (n = 240)
- Initial grows: 10,000 × 1.00583²⁴⁰ ≈ $40,400
- Contributions grow: 500 × [(1.00583²⁴⁰ − 1)/0.00583] ≈ $260,500
Future value ≈ $300,900 from $130,000 contributed — about $171,000 is pure growth.
Good to know
- The same $500/month started 10 years earlier roughly doubles the ending balance — time in the market beats timing it.
- Returns shown are nominal. After ~3% inflation, a 7% return is closer to 4% in real purchasing power.
- Fees compound against you: a 1% annual fee can erode 20%+ of your final balance over decades.
- Projections assume a steady rate; real markets are volatile, so treat the result as a long-run average, not a guarantee.
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Frequently Asked Questions
How does this calculator project investment growth?
It compounds your starting balance at the assumed return and adds your regular contributions, which themselves start compounding: FV = P(1+r)ⁿ plus the future value of the contribution stream. Small changes in return or time horizon produce large differences in the result.
What rate of return should I assume?
The S&P 500 has historically averaged about 10% per year nominal — roughly 7% after inflation — over long periods, but returns vary widely year to year and decade to decade. Conservative planning often uses 5-7% real to avoid overpromising.
How much difference do regular contributions make?
A large one. $500/month at 7% grows to roughly $260,000 in 20 years and $610,000 in 30 — most of the ending balance comes from compounding on early contributions. Consistency matters more than timing the market.
Should I look at nominal or inflation-adjusted results?
Inflation-adjusted (real) figures tell you what the money will actually buy. A nominal $1 million in 30 years is worth around $410,000 in today's dollars at 3% inflation. Use real returns when planning toward concrete goals like retirement spending.
How does my time horizon change the picture?
Compounding is exponential, so the last years contribute the most growth: at 7%, money doubles roughly every 10 years. Starting 10 years earlier can nearly double an ending balance even with the same total contributions — time in the market is the biggest lever you control.