Compound Growth Projector
Free compound interest calculator for investing. Project future value with contributions, expected returns, and compounding — see the snowball effect clearly.
Project future portfolio value with starting capital, regular contributions, expected returns, and compounding frequency. Compare “save more” vs “earn more” scenarios and see how time does most of the work.
What is a compound growth calculator?
A compound growth calculator (compound interest calculator for investing) estimates how money grows when returns are reinvested and optional contributions keep adding fuel. Instead of guessing “I’ll be rich someday,” you see a projected balance under clear assumptions — starting capital, contribution schedule, return rate, and time.
Why compounding matters more than perfect timing
Time in the market beats timing the market for most long-term investors. A modest monthly contribution invested for 20–30 years can outgrow a larger lump sum started late. This projector makes that visible: tweak contribution size vs return rate and see which lever moves the ending balance more. Deeper explainer: compound interest for investing.
How to use this free compound interest calculator
- Enter starting balance (what you have invested today).
- Add a contribution amount and how often you’ll invest.
- Pick a realistic expected annual return (be conservative).
- Choose years and compounding frequency.
- Compare scenarios — e.g. +$100/month vs +1% return.
Planning regular buys? Cross-check with our dollar cost averaging calculator. Measuring past results? Use the investment return calculator.
Realistic assumptions beat optimistic ones
- Fees and taxes: Lower your assumed return by 0.5–1%+ if you ignore costs in the model.
- Inflation: A $500k future balance buys less than today’s $500k — consider real (inflation-adjusted) returns.
- Sequence risk: Markets don’t return a flat 8% every year; the calculator shows a smoothed path, not a guarantee.
- Dividends: Model dividend reinvestment with our dividend & DRIP calculator.
Example: small contributions, long runway
$5,000 start + $300/month at 8% for 25 years is a common “wow” scenario in compound calculators — most of the ending value comes from growth on reinvested gains and contributions, not from the initial $5,000 alone. Run your own numbers above; then ask whether you can raise the contribution before chasing a higher (riskier) return assumption.
Frequently asked questions
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Projections are hypothetical and educational only — not financial advice. Actual results vary with markets, fees, taxes, and behavior.
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