The average American believes they'll need to save $1.8 million for their post-work years, according to Charles Schwab's "2024 401(k) Participant Study."

However, most Americans in their 50s have much less than that stashed away for retirement.

The average 401(k) account balance for people in their 50s is $212,400, as of the first quarter of 2024, according to data shared with CNBC Make It from Fidelity Investments, one of America's largest 401(k) providers. However, the average tends to skew higher due to a few larger 401(k) account balances.

On the other hand, the median 401(k) balance for people in their 50s is $64,300, per Fidelity's data.

Here's how much Americans have in their 401(k)s by age, according to Fidelity.

And that's just among people who have 401(k) retirement investment accounts. Some 20% of adults age 50 and over say they have no retirement savings at all, according to a 2024 AARP survey.

One reason Americans say they haven't been able to boost their retirement funds is due to the rising cost of living, Indira Venkateswaran, AARP's senior vice president of research, says in its report.

"Everyday expenses continue to be the top barrier to saving more for retirement, and some older Americans say that they never expect to retire," Venkateswaran says.

How Americans are rethinking retirement

Many Americans are beginning to rethink what their retirement years may look like.

For instance, nearly 60% of Americans plan to continue to work at least part time in retirement, according to Fidelity's "2024 State of Retirement Planning" study.

That strategy can be beneficial in two key ways, says Anne Lester, a retirement expert and author of "Your Best Financial Life: Save Smart Now for the Future You Want."

"Doing that allows you to save more and your savings will need to last for a shorter amount of time because the years you spend in full retirement will be shorter," she says. "So, you'd actually need less money than you otherwise would."

On top of working longer, "one of the most important things" you can do is to delay when you tap into your Social Security retirement benefits.

The earliest age you can begin receiving retirement benefits is 62, per the Social Security Administration.

However, depending on when you were born, you'd need to wait until you reach your full retirement age to get 100% of your retirement benefits. If you were born after 1960, your full retirement age is 67.

But it pays to delay if you can since your Social Security benefit increases by 8% for every year you wait to claim between your full retirement age and age 70.

"That's sort of the triple benefit of waiting to retire," Lester says. "You have longer to save, you have a smaller amount that you need to save and your Social Security income will be higher."

It's understandable that not everyone is able or wants to delay their retirement, though.

In that case, it's important to get a clear understanding of where you can cut back on your spending and redirect that toward your retirement savings, Lester says.

Anyone 50 and older can funnel extra money toward making catch-up contributions to their tax-advantaged retirement accounts such as 401(k)s and individual retirement accounts.

For 2024, workers age 50 and older can contribute an extra $7,500 to their 401(k), 403(b), governmental 457(b) or SARSEP plan.

Plus, reducing your spending while you're still working can help you adjust to a less expensive lifestyle that may be easier to manage during retirement, Lester says.

"Yes, you'll save more but you're also getting yourself used to a slightly less rich lifestyle," she says. "That means that when you retire, you'll already be used to a slightly lower standard of living, which is going to be easier to maintain."

Want to stop worrying about money? Sign up for CNBC's new online course Achieve Financial Wellness: Be Happier, Wealthier & More Financially Secure. We'll teach you the psychology of money, how to manage stress and create healthy habits, and simple ways to boost your savings, get out of debt and invest for the future. Start today and use code EARLYBIRD for an introductory discount of 30% off through September 2, 2024.

Plus, sign up for CNBC Make It's newsletter to get tips and tricks for success at work, with money and in life.