The maximum Social Security benefit in 2021 is $3,895 per month. There's a very good chance you won't get anywhere close to this amount -- and you need to be prepared for that reality. 

Here's why you're most likely going to get far less Social Security benefits than the maximum amount available. 

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The chances you'll max out your Social Security are slim

Maximizing your Social Security benefit is possible only under one condition. You must earn the maximum income subject to Social Security tax. 

Retirement benefits are based on your average indexed monthly earnings (AIME). But all wages don't necessarily count in determining this crucial average. There's a "wage base" limit each year. And once you hit the wage base limit, any income earned above it doesn't count in the calculation of your AIME (nor is it subject to Social Security tax). 

The wage base limit in 2021 is $142,800. Anything you earn above this amount in 2021 won't be counted when your AIME is determined in the future, so you won't get credit for it when your benefits are calculated. But if you earn less than this amount, then you won't be on track to earn the maximum Social Security check. 

Most people don't earn income at the wage base limit or above it, as this table from the Social Security Administration shows. 

Only about 6% of workers each year earn the maximum wage that counts toward Social Security. And, even if you're lucky enough to do that during 2021, or during several years throughout your career, there's another catch. Your AIME that determines your benefits is based on your 35 highest-earning years

That means if you want to earn the maximum Social Security benefit, you would need to be among that elusive 6% of workers earning the taxable maximum for a full 35 years. If you only pulled off those earnings for 34 or 33 years, some years of lower earnings would be factored in when your average wage is determined -- and you'd fail to earn the maximum possible benefit. 

Finally, there's one more requirement you'd have to fulfill to get the absolute maximum benefit. You'd have to wait until age 70 to start your retirement checks, which most people don't do. 

What can you expect your benefits to be?

As you can see, chances are your personal benefits are not going to come close to the maximum $3,895. And the bigger the gap between the maximum wage and your earnings, the more you'll fall short. That explains why the average monthly benefit is just $1,544 -- less than half the maximum. 

The size of your future checks, and how close you come to the average or maximum benefit, will depend on your income, how long you work, and when you start getting your checks. In general, however, you can expect that Social Security will likely replace around 40% of your pre-retirement income.

This probably won't be enough to live on for the vast majority of people, so it's important to save throughout your career so you have a nest egg to rely on to complement your Social Security.