An index fund owns a tiny slice of hundreds or thousands of companies. You don't pick winners — you own the market.
Over 20-year periods, low-cost index funds have outperformed roughly 90% of actively managed funds, primarily because of lower fees.
The strategy is simple: contribute regularly, reinvest dividends, and ignore the news. Volatility is the price of admission for long-term returns.
Key takeaways
- Diversification removes single-company risk for free.
- Low fees compound in your favor over decades.
- Time in the market beats timing the market.
Apply it with these calculators
Written and reviewed by
Keiron Brown, Psy.D.
Founder & Lead Educator, CalculatingWealth
Keiron Brown, Psy.D., is a clinical psychologist and the founder of Relationale LLC, which publishes CalculatingWealth. His doctorate is in psychology, not finance: he is not a registered investment adviser, accountant, or attorney, and nothing here is financial, investment, tax, or legal advice. His work here focuses on financial education, critical thinking, and decision-making — helping people understand the math behind money so they can plan with clarity and confidence. He writes about wealth building, retirement planning, investing literacy, budgeting, and the behavioral patterns that shape long-term financial outcomes.
Editorial standards: All educational content on CalculatingWealth is reviewed for accuracy, sourced from primary references where applicable (IRS, SSA, Federal Reserve, BLS), and updated when rules or rates change. Content is for educational and informational purposes only and does not constitute financial, investment, tax, or legal advice.
Not advice: Keiron Brown is not a registered investment adviser, broker-dealer, certified public accountant, enrolled agent, attorney, or licensed insurance producer. His work is educational in nature. See our full disclaimer.