Dollar-Cost Averaging Calculator
How Your Regular Investments Work
See how dollar-cost averaging automatically buys more shares when prices are low and fewer when prices are high.
Your Investment Results
Key Insight: By consistently investing, you automatically buy more shares when prices are low, lowering your average cost per share over time.
How DCA Works
When the market is down, your regular investment buys more shares. When the market is up, it buys fewer. Over time, this averages your cost.
Note: The chart shows a simplified price fluctuation pattern. Actual market movements are unpredictable.
Most people think investing requires watching the market every day, timing the bottom, or picking the next big stock. But the truth? The most powerful investing strategy most Americans use is already built into their paychecks-and they don’t even realize it.
If you’re contributing to a 401(k), you’re already doing dollar-cost averaging (DCA). Every time your paycheck hits your bank account, a fixed amount gets pulled out and invested automatically. You don’t think about it. You don’t check the news. You don’t panic when the market drops. You just keep going. That’s the power of dollar-cost averaging with paychecks.
How DCA Works (Without the Jargon)
Dollar-cost averaging means you invest the same amount of money at regular intervals-like every two weeks or every month-no matter what the market is doing.
Here’s how it plays out in real life:
- When the price of an ETF or mutual fund is high, your $300 buys fewer shares.
- When the price drops, that same $300 buys more shares.
- Over time, your average cost per share gets lower than if you’d bought everything at once.
Let’s say you invest $100 every month into an S&P 500 index fund. In one month, shares cost $50 each-you get 2 shares. Next month, the price drops to $40-you get 2.5 shares. The month after that, it spikes to $55-you get 1.8 shares. After three months, you’ve spent $300 and own 6.3 shares. Your average cost? About $47.60 per share. If you’d tried to time the market and invested all $300 at the high point, you’d only have 5.45 shares. You didn’t guess right. But you didn’t have to.
Why Paychecks Are the Perfect Vehicle for DCA
Paychecks solve the biggest problem most investors face: emotion.
When you see your portfolio drop 10% in a week, it’s hard not to want to sell. When it jumps 15%, it’s tempting to buy more right then. But emotions lead to bad decisions. Paycheck-based DCA removes you from the equation.
Think about it: if your $200 goes straight from your paycheck into your 401(k), you never even see it. You don’t miss it. You don’t question it. You don’t panic. You just keep earning and investing. That’s the magic.
According to Fidelity, this habit alone can turn small, consistent contributions into serious wealth. Someone putting $100 a month into an S&P 500 index fund with a 7% average annual return would have around $17,300 after 10 years. That’s not luck. That’s math.
Set-and-Forget: The Only Investment Strategy That Doesn’t Need You
The phrase “set-and-forget” isn’t just a buzzword. It’s the entire point.
Here’s how to make it happen:
- Enroll in your workplace 401(k) or 403(b). If your employer offers a match, contribute at least enough to get the full match. That’s free money.
- Set your contribution as a percentage of your paycheck-not a dollar amount. Why? Because when you get a raise, your contributions automatically go up too.
- Choose a low-cost index fund or target-date fund. Most plans offer these. They’re diversified, cheap, and require zero management.
- Turn on automatic escalation if your plan has it. Many now increase your contribution by 1% every year unless you opt out.
Once that’s done, you’re done. No apps to check. No alerts to ignore. No decisions to make.
For those without a 401(k), you can do the same thing through a brokerage account. Fidelity, Charles Schwab, and Vanguard all let you schedule automatic transfers from your checking account. You can start with as little as $10 or $25 a week. The platform buys fractional shares, so every dollar works for you-even if a single share costs $500.
What About Lump Sums? Should I Wait to Invest?
Some people get a bonus, tax refund, or inheritance and wonder: should I invest it all at once or spread it out?
Here’s the reality: if you have $10,000 sitting in cash, waiting to time the market is a trap. Markets tend to rise over time. The longer you wait, the more you risk missing out.
But that doesn’t mean you throw it all in on day one. If you’re nervous, use DCA even with a lump sum. Invest $1,000 a month for 10 months. You still get the benefit of averaging out the price-and you avoid the stress of putting everything in at a peak.
Just don’t stretch it out over years. That’s not DCA-that’s procrastination.
DCA vs. Lump-Sum Investing: The Numbers Don’t Lie
Some people point to Vanguard’s 2012 study that found lump-sum investing outperformed DCA about two-thirds of the time in rising markets. That’s true. If you had invested a lump sum at the exact bottom of a market crash, you’d have made more.
But here’s the catch: no one can predict the bottom.
What DCA gives you isn’t higher returns-it’s fewer sleepless nights. It’s consistency. It’s the ability to keep going even when the news is scary.
Let’s say two people each invest $1,000 per quarter. Jim invests $250 every two weeks. Tim invests his full $1,000 on the first day of each quarter. Over one quarter, the market dips in the middle. Jim ends up buying more shares at lower prices. He ends up with 12 more shares than Tim. Not because he’s smarter. Because he didn’t try to time it.
Who Should Use This Strategy?
Dollar-cost averaging with paychecks works best for:
- People with steady income-wages, salaries, freelance income you can count on
- Beginners who don’t know how to pick stocks or analyze markets
- Anyone who gets anxious watching market swings
- People saving for retirement over decades
It’s less ideal if:
- You’re trying to make quick money
- You have a large windfall and want to invest it all now (but even then, spreading it over 3-6 months helps)
- You’re not saving enough to begin with
The biggest failure isn’t using DCA. It’s starting and then stopping when the market drops.
What You Need to Get Started
You don’t need a finance degree. You don’t need a fancy app. You just need:
- A paycheck
- A retirement account (401(k), 403(b), IRA) or brokerage account (Fidelity, Schwab, Vanguard)
- 10 minutes to set up automatic contributions
Most employers handle the setup during onboarding. If you’re doing it yourself, log into your brokerage account, find the “automatic investments” or “recurring transfers” section, pick your investment, set the amount and date, and click save. Done.
As of 2025, 86% of new 401(k) plans automatically enroll employees. That means if you haven’t opted out, you’re already on this path. The question isn’t whether you’re doing it. It’s whether you’re doing it enough.
Common Mistakes (And How to Avoid Them)
Even with automation, people mess this up:
- Contributing too little. Experts recommend saving 10-15% of your income for retirement. If you’re only putting in 3%, you’re leaving decades of growth on the table.
- Not increasing contributions with raises. If you get a $5,000 raise, don’t just spend it. Put half of it into your retirement account. Let automation work for you.
- Changing investments during downturns. If your target-date fund drops, don’t switch to cash. That’s the opposite of DCA. Stay the course.
- Forgetting to review your portfolio. Automation doesn’t mean ignore it. Check your asset allocation once a year. Make sure you’re still on track.
The goal isn’t perfection. It’s persistence.
The Bigger Picture: Why This Strategy Will Outlast Trends
Wall Street loves complex products. Robo-advisors. AI-driven portfolios. Crypto ETFs. But the most powerful tool in personal finance hasn’t changed in 40 years.
It’s the same thing that built middle-class wealth in America: consistent, automatic investing through paychecks.
As of 2023, Americans had over $7.3 trillion in 401(k) accounts. That’s not because everyone is a financial genius. It’s because they set up a simple system and never touched it.
Millennials are adopting this even faster than older generations. Why? Because they’ve seen markets crash. They’ve seen people lose everything chasing trends. They know the real secret: wealth isn’t built by timing the market. It’s built by showing up-every paycheck, every month, every year.
You don’t need to be rich. You don’t need to be smart. You just need to be consistent.