Skip to main content

What is dollar-cost averaging? How does it work?

Allen Wastler

Posted on September 12, 2023

Allen Wastler is a former financial journalist with over 30-years of experience, including time at CNBC, CNN, and Knight-Ridder Newspapers.
Close up of two businesswomen working together on laptop
Magnifying Glass Icon 
This article will ...

Define dollar-cost averaging and what it is intended to do.

Provide a hypothetical example of the math involved in dollar-cost average investing.

Note the type of investor who may find dollar-cost averaging to be appealing.

The stock market gets a lot of attention, especially these days when it’s been on a mostly upward run.

When it's on the upswing, some people may feel they are missing out, especially if interest rates on regular savings accounts relatively low. On the other hand, there are down days — sometimes lots of them. The stock market does involve risk and there’s no guarantee that money invested in it will grow.

Indeed, an investment could disappear. So how can people strike a balance?

What is dollar-cost averaging?

Some turn to the long-term strategy that’s commonly called “dollar-cost averaging.” That’s where investors purchase stocks at regular intervals in fixed dollar amounts. The math behind this practice reduces the average purchase price of the stocks in the portfolio, regardless of which direction the market is moving. That’s because as the price of a particular stock rises, fewer units are bought. And if the price goes down, the reverse is true.

Let’s take a hypothetical example of dollar-cost average investing. Say an investor wants to put $120 into a particular company’s stock each month. If the stock cost $30 per share the first month, the investor would get four shares. If the price drops to $20 the next month, the investor gets six shares. If, in the third month, the stock price rises to $40, the investor gets three shares.

After three months, then, the investor would have 13 shares, but would have only paid an average price of roughly $27.

In short, with dollar-cost averaging, more shares are purchased when the price is low, and fewer are bought when the price is high, so the average purchase price per share is lower than the average share price. It’s important to note the dollar-cost averaging practice doesn’t eliminate risk. But the cost for taking on the risk is lower by lowering the average purchase price. (Related: Winning with a steady strategy)

Who should use dollar-cost averaging?

Some investors who get large sums of money periodically, say an annual executive bonus, use dollar-cost averaging to ease their money into the market, rather than investing the lump sum all at once. The practice would limit their loss in the case of a sudden market downturn. On the other hand, they would miss benefiting from a full gain should the market suddenly spike.

“If you’re looking to reduce your risk and control your emotions, or you fear that the market is heading for a drop, then dollar-cost averaging could be a viable strategy – even if that means forfeiting some potential upside,” said the Financial Industry Regulatory Authority in its examination of the practice. “You might consider how you would feel if you invested all of your bonus at one time and the market swooned soon after.”

Indeed, the risk is there. That’s why many investors often avoid or supplement investments in individual stocks by diversifying their portfolio to include mutual funds, bonds … and, yes, insurance.

The first step for any investor, though, is understanding the risk they are willing to accept … and doing the math.

Discover more from MassMutual...

Mutual fund and ETF basics

Tax advantages of life insurance

Need advice? Find a financial professional


Need a financial professional? Let us know ...

* = required

By submitting this request, I agree to receive e-mails and phone calls using automated technology from MassMutual, its financial professionals, affiliates or vendors on its behalf regarding MassMutual products and services, at the e-mail address and phone number(s) above, even if it is for a wireless phone. I understand I can contact a local financial professional directly to make a purchase without consenting to receive calls from MassMutual.

The information provided is not written or intended as specific tax or legal advice. MassMutual, its employees and representatives are not authorized to give tax or legal advice. You are encouraged to seek advice from your own tax or legal counsel. Opinions expressed by those interviewed are their own and do not necessarily represent the views of Massachusetts Mutual Life Insurance Company.