A surprising number of employees are missing out on a simple way to get 'free money'

The definitive guide to retirement savings plans
The definitive guide to retirement savings plans

If your company offers a 401(k) plan, they may also offer a 401(k) match.

"The company match is literally free money," Ramit Sethi writes in his personal finance book, "I Will Teach You To Be Rich."

The way it works is, your employer will match whatever contribution you put towards your 401(k) up to a certain amount. For example, if you choose to put four percent of your salary directly into your account, your employer will put that same amount in as well, in effect doubling your contribution.

But you only get their money if you put yours in first. And, according to a 2017 survey from 401(k) provider Betterment for Business, nearly a quarter of Americans aren't taking full advantage of this opportunity for free money.

How 401(k) retirement accounts changed everything
How 401(k) retirement accounts changed everything

After surveying more than 1,000 employees currently contributing to an employer-sponsored 401(k) plan, Betterment found that nearly a quarter of respondents aren't capitalizing on the opportunity: "89 percent of respondents were offered a 401(k) match by employers, but 23 percent didn't take full advantage of it. Of those 23 percent, 16 percent don't max out their match, and seven percent don't know if they do."

Keep in mind that Betterment only surveyed those enrolled in a 401(k) plan. Employees not contributing to their 401(k) plan at all are also missing out on the company match.

To take full advantage of the 401(k) match program if your company offers one, follow these three steps:

1. If you haven't already done so, enroll in a 401(k) plan.

2. Determine how much you need to contribute to get the full company match and start contributing at least that amount.

3. Set up automatic contributions so that your money is sent directly from your paycheck to to your 401(k) account. That way, you'll never even see the money you're saving and will learn to live without it.

Here's how much you should save at every age
Here's how much you should save at every age

Not all companies offer a 401(k) plan. If that's the case for you, there are other investment vehicles designed specifically for retirement, such as a Roth IRA or traditional IRA.

While these options don't offer "free money" in the same way, they do offer tax benefits and you have the option to set up automatic contributions.

Even if your employer does offer a 401(k), it's smart to consider more than one retirement savings vehicle, experts say. At the end of the day, however, what's more important than choosing what account to use is that you start saving now.

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Retirement in America is changing rapidly
Retirement in America is changing rapidly