Dollar-cost averaging (DCA) is the practice of investing a fixed amount of money at regular intervals—say, $200 every month—regardless of whether prices are up or down, rather than investing a lump sum all at once.
It matters because it removes the pressure of trying to time the market perfectly and automatically results in buying more shares when prices are low and fewer when prices are high, which can smooth out the average price paid over time.
How dollar-cost averaging actually works
Instead of guessing the 'right' moment to invest, you commit to a schedule—weekly, biweekly, or monthly—and invest the same dollar amount each time. When the share price is lower, your fixed amount buys more shares; when it's higher, it buys fewer.
Over many periods, this can result in a lower average cost per share than a single lump-sum purchase made at a random, potentially high, point in time—though it can also result in a higher average cost if prices trend steadily upward.
DCA with real numbers
Investing $300 monthly for four months at share prices of $30, $25, $20, and $25 buys 10, 12, 15, and 12 shares respectively—49 shares total for $1,200, an average cost of about $24.49 per share, which is lower than the simple average price of $25.
By contrast, if the same $1,200 had been invested as a lump sum on day one at $30 per share, it would have bought only 40 shares—nine fewer than the DCA approach in this particular price scenario.
DCA vs lump-sum investing
Historical studies generally show that lump-sum investing outperforms DCA more often than not, since markets tend to rise over long periods, meaning money invested earlier has more time to grow. DCA's main benefit is behavioral and psychological—it reduces the anxiety and regret risk of investing a large sum right before a downturn, and it fits naturally with investing from a regular paycheck.
One widely cited analysis found lump-sum investing beat a 12-month DCA schedule roughly two-thirds of the time when investing in US stocks, but the DCA approach still resulted in smaller worst-case losses during the periods when markets fell shortly after the initial investment.
Automating contributions to make DCA effortless
Most brokerages and retirement plans allow you to set up automatic recurring transfers—for example, $250 pulled from a checking account on the 1st and 15th of each month directly into an index fund. This turns DCA from something you have to remember into a default behavior, which reduces the temptation to skip contributions during a downturn or delay investing while waiting for a 'better' entry point.
A 401(k) with payroll deductions is a built-in form of DCA: each paycheck automatically buys shares at that day's price. Replicating this in a taxable brokerage account or IRA with automatic transfers on payday extends the same discipline to money outside an employer plan.
When DCA makes the most practical sense
DCA is most naturally suited to situations where money arrives over time anyway, such as investing a portion of each paycheck, rather than deciding how to invest a windfall you already have in hand, like an inheritance or bonus. For a lump sum already sitting in cash, spreading it out over, say, 6 to 12 months is a compromise some investors use to reduce the emotional risk of a poorly timed lump sum, while acknowledging it may modestly reduce expected long-term returns.
For ongoing income, there generally isn't a meaningful alternative to DCA, since money simply isn't available to invest as a lump sum before it's earned.
Common mistakes
- Assuming DCA always beats lump-sum investing—historically it doesn't, on average, in rising markets.
- Stopping contributions during downturns, which defeats the purpose of buying more shares at lower prices.
- Treating DCA as a way to avoid all investment risk rather than a way to manage timing risk specifically.
- Confusing DCA with automatically 'buying the dip'—DCA invests on a schedule, not based on price movements.
- Using DCA to justify holding a large lump sum in cash indefinitely instead of setting a defined schedule to invest it.
Simulate a DCA schedule against a lump-sum scenario in Aurora's investing track.
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Open Decision Lab →Frequently asked questions
Is dollar-cost averaging better than investing a lump sum?
Not necessarily; historically, lump-sum investing has outperformed DCA more often because markets tend to rise over time, but DCA can reduce emotional decision-making.
How often should I dollar-cost average?
Common intervals are weekly, biweekly, or monthly, often aligned with when you receive a paycheck.
Does DCA guarantee lower average costs?
No, it only lowers average cost per share if prices fluctuate; in a steadily rising market it can result in a higher average cost than a lump sum invested early.
Can I use dollar-cost averaging with any investment?
Yes, it's commonly applied to index funds, ETFs, and individual stocks, and is the default approach for many retirement account contributions.
Is dollar-cost averaging the same as automatic investing?
They're closely related; automatic recurring contributions to an investment account are a practical way of implementing dollar-cost averaging.