There are plenty of scary statistics out there about Americans' retirement savings (or lack thereof), but there's a particularly worrisome trend when it comes to people nearing retirement age: Too many of them aren't saving anything.

In fact, 48% of American adults over age 55 don't have any retirement savings, according to research from the U.S. Government Accountability Office. Considering these people are just a few years away from retiring, that means they'll either need to kick their savings into high gear ASAP or continue working well into their 70s and beyond (assuming they're physically able to work that long).

Dollar bills with a stopwatch

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Some people may eschew saving on their own because they think they'll be able to depend on Social Security benefits during retirement. But the average benefits check is just $1,300 per month, according to the Social Security Administration, and the Bureau of Labor Statistics claims that the average American age 65 and up spends around $3,800 per month.

In other words, unless you're OK with dramatically limiting your spending during retirement, you'll need some personal savings alongside Social Security benefits if you want to comfortably enjoy your golden years. While building a strong nest egg from scratch starting in your 50s won't be easy, it's better to save what you can than do nothing.

Saving for retirement: Better late than never

Although it's more difficult to amass significant savings when you're off to a late start, who isn't up for a good challenge? And if the alternative is not saving anything and being forced to rely solely on Social Security for the rest of your life, jump-starting your retirement savings now is your best option.

To get started, first set a goal for yourself. If you're in your 50s and don't have a penny saved, be realistic and know that you won't be a millionaire by 65 (unless you win the lottery or inherit a mass fortune, of course). But say you want to be able to retire by age 70, and you expect to need, say, $45,000 each year during retirement. Social Security will help some, and you can get a rough estimate of how much you'll receive by using the Social Security Administration's benefits calculator. So if you find out you'll be receiving, say, $1,500 per month (or $18,000 per year) in benefits, that means you'll need to come up with the other $28,000 per year on your own.

To figure out how much you'll need to have saved by the time you retire, multiply that number by 25. This is based on the 4% rule, which states that if you withdraw 4% of your savings the first year of retirement and then adjust that number each subsequent year for inflation, your money will last around 30 years. So in this case, if you expect to withdraw $28,000 during the first year from your retirement fund, you'll need to start with a nest egg of $700,000.

That number is probably a bit shocking, right? It's understandable -- but don't throw your retirement plans out the window just yet. Yes, $700,000 is a lot of money. And if you're, say, 50 years old now with nothing saved for retirement, you'd need to save just over $1,400 per month for 20 years to reach that goal, assuming you're earning a 7% annual return on your investments.

However, not all is lost. Say you can only save $500 per month, and you do so for 20 years. You'd end up with around $425,000, and by using the 4% rule, that means you could withdraw around $17,000 the first year of retirement (in addition to Social Security benefits).

Will that be enough to get by during retirement? It depends on your lifestyle. You may need to make some sacrifices, but any amount you can save is better than nothing.

Maximizing Social Security

In addition to saving as much as you can on your own, you can also delay claiming Social Security benefits to receive bigger checks. You're allowed to start claiming benefits as early as age 62 (which is the most popular age to claim), but for every month you wait after that age (up until age 70), you'll receive slightly bigger checks.

So if you delay retirement and wait to claim benefits until age 70, you'll see two advantages: bigger Social Security checks, and more time to continue working and contributing to your retirement fund. The increase in benefits can make a significant difference, too -- especially if money is tight during retirement.

For example, if your full retirement age (the age at which you'll receive 100% of the benefits you're theoretically entitled to) is 67, by waiting until age 70 to claim, you'd receive a 24% boost on top of your full amount. But if you claim early at 62, your benefits would be slashed by 30%.

So if your full amount that you'd receive by claiming at 67 is, say, $1,500 per month, if you claimed at 62, you'd receive just $1,050 per month. But by waiting until age 70, you'd receive monthly checks of $1,860 -- for life. If you're going to be at least somewhat reliant on Social Security during retirement, it helps to have an extra $800 each month.

If you're in your 50s and behind on your savings, it may feel like you've missed your chance. But while it's often an uphill battle to save when you're older, it's never too late to prepare for retirement. And the sooner you begin, the more you'll thank yourself later.