What is dollar-cost averaging?
Dollar-cost averaging (DCA) is the practice of investing a fixed dollar amount at regular intervals, for example $500 a month into a diversified ETF, rather than investing a larger sum all at once. It smooths out the average price you pay over time and removes the pressure of picking a single "right" moment to invest. It does not guarantee a better outcome than investing a lump sum, and which approach performs better in hindsight depends entirely on what the market does after you start.
How dollar-cost averaging works
Instead of deciding when to invest a full amount, you commit to investing a set dollar figure on a fixed schedule, weekly, fortnightly, or most commonly monthly. At each interval, the same dollar amount buys however many units the current price allows. When the price is lower, that amount buys more units. When the price is higher, it buys fewer. Over many intervals, this produces an average cost per unit that reflects the full range of prices during the period, rather than whatever the price happened to be on one particular day.
DCA is not a market-timing technique, it is essentially the opposite. It replaces the decision of when to buy with a decision to buy on a schedule regardless of price, which is precisely what makes it easy to automate and sustain.
Who uses it
Most working Australians already dollar-cost average without labelling it as such: employer super contributions arrive most pay cycles and are invested at whatever price applies that day. Investors who set up an automatic monthly buy order for an ETF are doing the same thing deliberately with money outside super. DCA is also commonly used by investors who receive a lump sum, such as an inheritance, bonus, or the proceeds of a sale, and choose to stagger it into the market over several months instead of investing it all on a single day.
When it tends to suit, and when it doesn't
DCA suits money you don't yet have, ongoing income you're investing as it arrives, since there is no lump sum decision to make in the first place. It also suits investors who would otherwise delay investing a lump sum indefinitely while waiting for a better entry point, a wait that has no natural end point. It tends to suit investors less well when a lump sum is already available and sitting in cash: in that case, the choice isn't between DCA and doing nothing, it's between DCA and investing the full amount now, and holding money back has its own cost.
Example
The figures below are illustrative only, not a real ETF or historical price series. An investor contributes $500 on the first of each month into a diversified ETF over six months, while the unit price moves around:
| Month | Unit price | Amount invested | Units bought |
|---|---|---|---|
| 1 | $40.00 | $500 | 12.50 |
| 2 | $36.00 | $500 | 13.89 |
| 3 | $32.00 | $500 | 15.63 |
| 4 | $38.00 | $500 | 13.16 |
| 5 | $44.00 | $500 | 11.36 |
| 6 | $42.00 | $500 | 11.90 |
Total invested: $3,000. Total units bought: approximately 78.44. That works out to an average cost of roughly $38.25 per unit, below the simple average of the six monthly prices ($38.67), because more units were bought during the cheaper months. If the $3,000 had instead been invested as a lump sum in month 1 at $40.00, it would have bought exactly 75 units, fewer than the DCA approach in this particular sequence of prices. A different sequence of prices, for example one that rose steadily from month 1, would flip this comparison in favour of the lump sum.
Advantages
- Removes the timing decision: there is no need to judge whether now is a good time to invest, the schedule decides for you.
- Matches how most people are paid: investing a portion of each pay cheque is a natural fit for a recurring schedule.
- Avoids a single worst-case entry point: no one purchase determines the whole outcome, which reduces regret if a lump sum had been invested right before a fall.
- Easier to sustain: an automated recurring purchase requires no ongoing decision-making, which helps investors stay invested through volatility.
Limitations
- Tends to underperform a lump sum in rising markets: money held back to invest later earns nothing while it waits, and share markets have historically risen more often than they've fallen over long periods.
- Doesn't prevent a loss: it spreads the entry price across a period, it does not protect against a genuine sustained decline in the investment's value.
- Brokerage can add up: frequent small purchases may carry disproportionate brokerage fees depending on your broker's pricing, worth checking before committing to a very frequent schedule.
- Isn't a substitute for having the money: DCA describes how to invest a lump sum you already hold, or income as it arrives. It isn't a way to invest money you don't yet have.
Common mistakes
- Treating it as loss protection: DCA changes your average entry price, it does not stop the investment from falling in value.
- Pausing contributions during a downturn: this removes the main benefit, buying more units while prices are low.
- Second-guessing the schedule: skipping a purchase because the price "feels high" reintroduces the market-timing decision DCA is meant to remove.
- Ignoring brokerage drag: investing very small amounts very frequently can mean fees eat a meaningful share of each contribution.
- Leaving an existing lump sum in cash indefinitely: using DCA as a reason to delay investing money that's already available, rather than as a genuine staggered plan with an end date.
Frequently asked questions
What is dollar-cost averaging?
Dollar-cost averaging (DCA) means investing a fixed dollar amount at regular intervals, for example $500 a month, regardless of whether the price is up or down that day. It replaces a single timing decision with a repeated, scheduled one.
Is DCA better than investing a lump sum?
Not consistently. Because share markets rise more often than they fall over long periods, investing a lump sum immediately has outperformed DCA in most historical comparisons, since the full amount spends more time invested. DCA tends to do better when markets fall or stay flat after you start. Neither approach is guaranteed to win, since future returns cannot be known in advance.
Can DCA reduce investment risk?
It reduces one specific risk: putting a large sum in right before a downturn. Spreading purchases over time means no single purchase date determines your entire outcome. It does not reduce market risk generally, a sustained decline still reduces the value of every unit you own, regardless of when you bought them.
Does DCA guarantee profits?
No. DCA is a purchasing schedule, not a return guarantee. If the price of the investment falls and never recovers, DCA still produces a loss, it simply changes the average price paid along the way. No investment strategy can guarantee a profit.
How often should someone invest?
There is no single correct frequency. Many Australians naturally invest monthly, aligned with pay cycles, since that keeps the process automatic and avoids re-litigating the decision every payday. What matters more than the exact frequency is consistency and keeping brokerage costs proportionate to the amount invested each time.
Official sources
- ASIC MoneySmart - how to invest, including regular investing strategies
- ASIC MoneySmart - managed funds and ETFs
Model a regular investing plan
Use the ETF Growth Calculator to project a regular monthly contribution over time, or see how those contributions compound in the Compound Interest Calculator. If you're investing in dividend-paying shares or ETFs, the Dividend Yield guide explains how to read the income side of your return. Regular investing is also a core part of most FIRE plans, since a consistent monthly contribution is usually what drives the portfolio.