# What is dollar-cost averaging, and does it work?

> Dollar-cost averaging is investing a fixed amount on a schedule, so you buy more shares when prices dip.

Source: https://www.walletprep.com/learn/dollar-cost-averaging/ · Updated 2026-10-04 · Investing

Dollar-cost averaging means investing the same amount on a regular schedule, like $200 every month, no matter what prices are doing. You buy more shares when prices are low and fewer when they are high, and you never have to guess the right moment to buy.

## Key facts
- **Same dollars, changing shares.** When you invest a set amount each time, the number of shares you get depends on the price. Low prices buy more shares, high prices buy fewer, so your average cost per share tends to come out lower than the average price.
- **It takes timing off the table.** You don't have to predict highs and lows. The schedule decides when you buy, which helps you avoid panic selling in drops and rushing in after big gains.
- **Two different situations.** Investing from each paycheck is dollar-cost averaging by default, and it is simply investing money as you earn it. Holding a lump sum in cash and feeding it in slowly is a choice, and it has a cost.
- **It does not prevent losses.** If an investment keeps falling for years, buying it every month still loses money. Dollar-cost averaging works with a broad, diversified fund you plan to hold for a long time.

## How it works month to month
Say you invest $200 on the first of each month into a broad index fund. When the price is $50, you get 4 shares. When it falls to $25, the same $200 gets 8 shares. You don't change anything. The math does the work.
Over time you end up owning more shares bought at low prices than at high prices. That is why your average cost per share is usually below the simple average of the prices you paid. It does not mean every purchase was a good one.

## You are probably already doing it
If money comes out of each paycheck into a 401(k), 403(b) or IRA, that is dollar-cost averaging. Here, there is no real alternative. You can't invest next year's paychecks today, so investing each one as it arrives is the best you can do.
The habit is what matters. Steady contributions, raised a little each year, do most of the work in building a retirement balance.

## Lump sum or spread it out
The real choice comes when you have a large amount at once, such as a bonus, an inheritance or money from selling a car. You can invest it all now, or split it into equal parts over several months.
Money invested sooner spends more time in the market, so spreading it out often ends with a lower balance. FINRA notes that holding cash and investing gradually has lower risk but often produces lower returns than investing a lump sum.
Spreading it out has one real advantage: if prices drop soon after you start, the cash you held back buys at the lower price, and you feel less regret. If investing it all at once would keep you awake, splitting it over 6 to 12 months is a reasonable middle path.

## Setting it up
Choose a broad, low-cost fund, such as a total market index fund or a target-date fund. Then choose an amount you can keep up even in a tight month. A smaller amount you never skip is better than a big one you stop.
Most brokerages and IRA providers let you schedule automatic deposits and automatic purchases. Line the date up with your payday so the money moves before you can spend it. Then raise the amount each time you get a raise.

## A worked example: Kim's $200 a month through a dip
Kim, 31, invests $200 on the first of each month in an index fund. Over four months the price goes $50, $40, $25, then back to $50. The prices are made up.

- Month 1 at $50: $200
- Month 2 at $40: $200
- Month 3 at $25: $200
- Month 4 at $50: $200
- Total invested: = $800
- Shares bought: 21
- 21 shares at $50: $1,050
- Total invested: −$800
- Gain on paper: = $250

1. Shares bought: $200 ÷ $50 = 4, $200 ÷ $40 = 5, $200 ÷ $25 = 8, then 4 again. 4 + 5 + 8 + 4 = 21 shares.
2. Her average cost is $800 ÷ 21 = about $38.10 a share, below the average price of ($50 + $40 + $25 + $50) ÷ 4 = $41.25.
3. 21 × $50 = $1,050. All $800 in month 1 would buy 16 shares, worth $800 now. Had prices only risen, the lump sum would have won.

### What $200 a month grows to over 20 years at a few assumed yearly returns (real returns vary and can be negative)

| Annual return | Balance after 20 years | Of which growth |
| --- | --- | --- |
| 4% | $73,355 | $25,355 |
| 6% | $92,408 | $44,408 |
| 8% | $117,804 | $69,804 |

## Common mistakes
- **Pausing when prices fall.** Stopping contributions during a drop skips the months when your money buys the most shares. It turns a calm plan back into market timing.
- **Spreading a lump sum for years.** Feeding a windfall in over three or four years leaves most of it sitting in cash for a long time. If you spread it out, keep the window short.
- **Using it on a single risky stock.** Buying more of one company every month as it keeps falling just piles more money onto one bet. Use the method with broad, diversified funds.

## Questions people ask
### Is dollar-cost averaging a good strategy?
For money you earn and invest from each paycheck, yes. It is simply investing as you go. For a lump sum, investing it sooner has often come out ahead, but spreading it over a few months can make it easier to start.

### How often should I dollar-cost average?
Matching your pay schedule, every two weeks or every month, works well. The exact day matters far less than sticking with it.

### Does dollar-cost averaging work in a down market?
It is when the method helps most, because each fixed payment buys more shares. Those extra shares can grow if prices recover, though there is no promise when or whether they will.

### What should I do with the cash while I spread out a lump sum?
Keep it in an insured high-yield savings account or a money market account so it earns interest and stays safe until each scheduled purchase.

## Do this today
Log in to your IRA or brokerage account and set up an automatic monthly investment into one broad index fund, dated for the day after payday. Even $25 a month starts the habit.

## Sources
- [Investor.gov (SEC): Dollar Cost Averaging](https://www.investor.gov/introduction-investing/investing-basics/glossary/dollar-cost-averaging)
- [FINRA: The Benefits and Limitations of Dollar-Cost Averaging](https://www.finra.org/investors/insights/dollar-cost-averaging)

_General education, not personalized financial, tax or legal advice. Figures are examples. Check current rates and limits before you act._