There's only one requirement to be eligible for a spousal Social Security benefit: marry a qualifying worker. That's one who has worked long enough to earn at least 40 work credits -- about 10 years -- or more.

But being eligible for a spousal benefit and actually getting one are two different things. Below, we'll take a closer look at why you might not get a spousal benefit, and why that could actually be a good thing.

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How the government calculates Social Security and spousal benefits

Calculating a spousal benefit always begins with calculating the worker's benefit. The first step is to determine their average indexed monthly earnings (AIME) by totaling their income from their 35 highest-earning years, adjusted for inflation, and dividing that by 420 -- the number of months in 35 years.

Then, their AIME goes into the Social Security benefit formula in effect in the year they turned 60. Here's a closer look at the 2024 formula:

  1. Multiply the first $1,174 of your AIME by 90%.
  2. Multiply any amount greater than $1,174 up to $7,078 by 32%.
  3. Multiply any amount greater than $7,078 by 15%.
  4. Add your results from the steps above and round down to the nearest $0.10.

The only parts of the formula that change annually are the two dollar amounts, known as the bend points. The IRS keeps a table where you can view all the bend points from previous years if you'd like.

The result of this formula is the primary insurance amount (PIA), but that's not always the same as the worker's benefit. The worker must claim Social Security at their full retirement age (FRA) to get this amount. Signing up earlier reduces the worker's benefit by up to 30%, while delaying Social Security as late as 70 could boost the worker's benefit by up to 32%.

Spousal benefits are based on the worker's PIA. The most you can get is 50% of their PIA, but you could wind up with as much as 35% less, depending on how early you apply for benefits. There's no way to boost spousal benefits by delaying Social Security past your FRA, though.

A spousal benefit is the only option for someone who never worked, or who didn't work long enough to qualify for Social Security on their own. But a lot of people today are dually eligible for a retired worker's benefit and a spousal benefit. That's where things get interesting.

How do you know what kind of benefit you'll get?

Your Social Security checks will equal the larger of your own retirement benefit or your spousal benefit. You cannot claim a full worker's benefit on your own, plus your complete spousal benefit on top of it. If the benefit you qualify for on your own is larger than your spousal benefit or your spouse hasn't applied for Social Security yet, you'll only get your own benefit.

It's slightly more complicated if your spouse is already on Social Security and your spousal benefit is larger than your own benefit. Technically, the Social Security Administration pays out your own benefit, and then it gives you a portion of the spousal benefit you're eligible for, so your final check amount equals your spousal benefit. For example, if your own benefit is worth $1,000 per month and your spousal benefit is worth $1,500 per month, the government would pay your $1,000 benefit plus $500 of your spousal benefit. So your checks would still be worth $1,500 each.

If you want to know which type of benefit you'll get, the easiest way to do this is to make a my Social Security account and have your spouse do the same. After setting up the account, you'll get access to a calculator that enables you to estimate your Social Security benefit at any age. You can also estimate future spousal benefits by entering your spouse's PIA.

Keep in mind that this tool only gives you estimates based on your work history to date. Your actual benefit could rise or fall over time depending on what happens to your income or marital status. Check back every couple of years to see if your estimated Social Security benefits have changed, and update your claiming strategy accordingly.