What Is Dollar-Cost Averaging?
Dollar-cost averaging (DCA) means investing a fixed amount of money at regular intervals (usually monthly), regardless of whether the market is up or down.
- Market up? You buy fewer shares (but your existing shares are worth more).
- Market down? You buy more shares at a discount (lowering your average cost).
- You never try to predict what the market will do next.
Why DCA Works
- Removes emotion: You don’t panic sell during crashes or FOMO buy during bubbles.
- No timing required: Studies show that even investing at the worst possible time each year still beats waiting for a “perfect” entry point.
- Builds habits: Automatic investing becomes a habit. Habits build wealth.
- Reduces regret: You never feel like you “bought at the top” because you’re always buying.
DCA vs Lump Sum: The Data
Vanguard research shows that lump-sum investing beats DCA about 68% of the time (because markets go up more than down). However:
- Most people don’t have a lump sum - they earn monthly, so DCA is natural
- DCA reduces maximum drawdown (your worst-case scenario is better)
- The psychological benefit of DCA means people actually stick with it (vs panic-selling a lump sum during a crash)
Bottom line: If you have a lump sum, invest it all now (statistically optimal). If you earn monthly, invest monthly (DCA). Either way, the worst strategy is waiting.
How to Set Up DCA (5 Minutes)
- Open your brokerage account (Fidelity, Schwab, or Vanguard)
- Go to “Automatic Investments” or “Recurring Purchases”
- Choose your fund (VTI, VOO, or target-date fund)
- Set the amount ($50, $100, $500 - whatever you can afford consistently)
- Set the frequency (monthly, on payday)
- Forget about it. Check quarterly at most.
DCA in Action: Real Numbers
$500/month invested in the S&P 500 (VTI) starting January 2020:
- March 2020: Market crashes 34%. Your $500 buys shares at a huge discount.
- You kept investing through the crash (most people panic-sold).
- By December 2025: Your $36,000 invested is worth ~$58,000 (61% total return).
- If you had stopped investing during the crash: you’d have ~$42,000 instead.
The investors who kept their automatic investments running through COVID made significantly more than those who paused.
Common DCA Mistakes
- Stopping during crashes: This is the worst time to stop. Crashes are when DCA works best (you’re buying cheap).
- Checking too often: Daily portfolio checks lead to emotional decisions. Set it and forget it.
- Inconsistent amounts: Pick an amount you can sustain for years. Consistency matters more than size.
- Waiting to start: The best time to start DCA was yesterday. The second best is today.
Source: Vanguard Research “Dollar-cost averaging just means taking risk later” (2023), S&P 500 historical data