The financial toll of divorce can be especially hard on seniors living on fixed incomes. Some qualify for Social Security benefits, but they may not get much if they only worked sporadically or earned little during their careers.

Fortunately, not all divorced people have to rely solely upon their own income history. Below, we'll take a closer look at how the government calculates Social Security benefits and why your ex might be your ticket to much bigger checks.

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How the government calculates Social Security benefits

A worker's Social Security benefit depends on how much they've paid in Social Security taxes throughout their careers. Specifically, the government looks at how much income you paid Social Security taxes on during your 35 highest-earning years, adjusted for inflation. It totals these figures and divides them by 420 -- the number of months in 35 years -- to arrive at your average indexed monthly earnings (AIME).

Your AIME then goes into the Social Security benefit formula. The result of this is the primary insurance amount (PIA). That's how much you get if you claim Social Security at your full retirement age (FRA). FRA is somewhere between 66 and 67 for today's workers.

Those who choose to claim at other ages have their benefits adjusted accordingly. Claiming early reduces your monthly checks by up to 30%, while delaying Social Security past your FRA grows your checks until you reach your maximum benefit at 70, which could be up to 32% more than your PIA.

This is the only way to calculate benefits for adults who have never been married. But for married couples, the Social Security Administration also checks to see if they qualify for a spousal Social Security benefit. They'll get this instead if their spousal benefit is worth more than what they qualify for on their own.

A spousal benefit is worth up to half of the worker's PIA. However, you could get less than this if you claim before your FRA. For example, if your partner qualifies for a $2,000 benefit at their FRA, you could be eligible for $1,000 if you delay until your FRA. But if you begin right away at 62, you'd only get $650 per month if your FRA was 67 or $700 per month if your FRA was 66.

Unfortunately, you can't grow spousal benefits further by applying after your FRA. You also can't apply for spousal benefits unless the worker is already claiming -- at least, you can't if you're currently married.

Ex-spouses may qualify for spousal Social Security benefits too

Spousal Social Security benefits are available to ex-spouses too, as long as you meet the following criteria:

  • You're at least 62 when you apply for benefits.
  • You were married to your ex for at least 10 years and have not remarried.
  • Your ex is currently receiving Social Security OR you have been divorced for at least two years.

You're eligible for a spousal Social Security benefit if you meet these criteria, assuming the spousal benefit is larger than what you qualify for on your own. And don't worry if your ex has remarried. You claiming a spousal benefit won't affect their new spouse's ability to do the same. Similarly, if their new spouse is already claiming a benefit, you'll still be able to do so if you check the boxes above.

To apply for a spousal Social Security benefit, you'll need to provide the Social Security Administration with some key information, including:

  • Your Social Security number
  • Your date of birth
  • Your ex's Social Security number, if known
  • The date of your marriage
  • The date of your divorce

If you don't have some of this information, call the Social Security Administration or set up an appointment at your local Social Security office. A representative may be able to help you collect the information you need.

Keep in mind, the Social Security application process can take several weeks, and you don't receive your first check until the month after benefits are due. For example, if you want your checks to begin in April, you won't actually see any money in your bank account until May. So get the ball rolling soon if you want your benefits as quickly as possible.