You'll probably rely on your Social Security benefits to pay the bills in retirement. In fact, those benefits may even be your sole source of income. That's why understanding when you're allowed to claim benefits and filing for them at the right time matter.

You're entitled to your full monthly Social Security benefit, which is based on your earnings history, once you reach full retirement age. But shockingly, 76% of Americans don't know what their FRA is, according to a Nationwide survey. Failing to learn your FRA could leave you with a permanently reduced benefit and many years of financial struggles to follow.

Older person at table holding a spoon over a bowl.

Image source: Getty Images.

Why it's important to wait until FRA to claim Social Security

FRA is a function of your year of birth. Consult this table to see what yours is:

Birth Year

Full Retirement Age




66 and 2 months


66 and 4 months


66 and 6 months


66 and 8 months


66 and 10 months

1960 or later


Data source: Social Security Administration.

You are allowed to file for Social Security as early as age 62, but for each month you claim benefits ahead of FRA, they'll be reduced on a permanent basis. Filing at 66 with an FRA of 67 will cut your benefits by 6.67% -- and maybe that's not so bad. But if you claim Social Security at 62 with that same FRA, you'll be looking at a 30% reduction to your benefits for life. That's a hit you probably can't afford to take, especially if you expect Social Security to serve as your primary income source.

The average Social Security recipient today collects about $1,500 a month in benefits. Filing at age 66 with an FRA of 67 will leave you with $1,400 a month instead. Filing at 62, meanwhile, will give you just $1,050 a month. Ouch.

Keep in mind that FRA applies to spousal benefits, too. If you're planning to collect Social Security based on a current or former spouse's work history, as opposed to your own, you'll need to wait until you reach FRA to get the full amount you're entitled to. Otherwise, your spousal benefit will be reduced if you file early. However, you can't grow a spousal benefit the same way you can grow a benefit based on your own earnings record, so once you reach FRA, you might as well claim it.

Avoiding a huge mistake

If you expect to depend heavily on Social Security in retirement, commit your FRA to memory and aim to wait until that age -- or beyond -- to file for benefits. You can actually delay your filing past FRA and boost your benefits by 8% a year in the process up until age 70.

What if you already filed for Social Security before FRA because you didn't know the age at which you could claim your benefits in full? There's still an option. If it's been less than a year since you put in that claim, you can withdraw your benefit application and file again at FRA, thereby avoiding a lifelong hit to your benefits. To take advantage of this do-over, though, you'll need to repay the Social Security Administration every dollar it paid you. If you've spent that money already, that may not be feasible. A better bet, therefore, is to avoid filing early unless you have a truly compelling reason to do so.

Of course, to avoid filing early, you'll need to know what that actually means, so figure out what your FRA looks like sooner rather than later. Even if you're not retiring for many years, it still pays to keep that key number in the back of your mind.