Investment Calculator

How the investment calculator works

Enter your initial investment, planned monthly contribution, expected annual return, and time horizon. The calculator projects your portfolio's future value using monthly compounding, breaks down how much comes from your contributions versus investment growth, and shows a year-by-year growth chart.

The power of compound growth

Investing $500/month at 7% return for 20 years costs you $130,000 out of pocket. But your final balance is roughly $300,851 — meaning compound growth contributed over $170,000, more than your total contributions. The earlier you start, the larger this "free money" slice becomes.

Realistic return assumptions

• S&P 500 index funds: ~10% nominal / ~7% inflation-adjusted
• Balanced 60/40 portfolio: ~7–8%
• Bond-heavy portfolio: ~4–5%
• Real estate (REITs): ~8–9% (with higher volatility)

Always use inflation-adjusted returns (typically 2–3 percentage points lower than nominal) for retirement planning. A "10% return" looks great, but only ~7% of it is real wealth growth.

Investment principles that beat the math

• Start early: 10 extra years of compounding often beats doubling your contribution
• Keep costs low: index funds (0.03% fee) beat managed funds (1%+ fee) over decades
• Don't time the market: time in the market beats timing the market
• Diversify: never bet your future on a single stock or sector
• Automate: set up automatic monthly investing so you never skip a contribution