Everyone wants to buy low and sell high. The problem is nobody knows when low actually is. Dollar-cost averaging is what you do instead.
The Basic Idea
Dollar-cost averaging is the practice of investing a fixed dollar amount on a regular basis, regardless of the share price. Instead of trying to find the perfect moment to invest a lump sum, you invest the same amount every month – whether the market is up, down, or sideways.
When prices are high, your fixed amount buys fewer shares. When prices are low, it buys more. Over time, your average cost per share smooths out.
A Simple Example
Say you invest $200 every month into an S&P 500 index fund:
| Month | Price per Share | Shares Bought |
|---|---|---|
| January | $50 | 4.0 |
| February | $40 | 5.0 |
| March | $45 | 4.4 |
You spent $600 total and bought 13.4 shares. Your average cost was $44.78 per share – lower than two of the three months. The dip in February worked in your favor automatically, without you having to do anything.
Why It Works
It removes emotion. The biggest reason most investors underperform isn’t bad stock picks – it’s buying high when things feel great and selling low when things feel scary. A fixed schedule removes that temptation entirely.
It keeps you in the market. Volatility is a normal part of investing – dollar-cost averaging helps you view periods of weakness as buying opportunities rather than reasons to panic.
It makes investing manageable. $200 a month is less intimidating than deciding whether to deploy $2,400 all at once. Consistency beats timing.
The One Limitation Worth Knowing
Over long periods of time, dollar-cost averaging tends to produce lower returns compared with lump-sum investing – if you happen to invest a large amount right before a sustained bull run, you’d have done better going all in. But since nobody can predict that, DCA is the more reliable strategy for most people.
How to Set It Up
Choose a broad-market index fund or ETF you believe in for the long term, decide on a fixed amount that fits your budget, then automate it on a recurring schedule – weekly, monthly, whatever works.
At Fidelity, Schwab, or Vanguard, you can set up automatic recurring investments in a few minutes. Pick a date – ideally right after payday – and let it run.
You don’t need to check it every week. That’s the point.
If You Have a 401(k), You’re Already Doing It
If you contribute a set amount from every paycheck to your retirement account, you’re already using dollar-cost averaging. Every contribution buys shares at whatever price they happen to be that day. You’ve been doing this correctly all along. Fidelity
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