The formula starts with your earnings history, not your disability

Social Security does not calculate your SSDI payment based on how disabled you are or how much money you need. Instead, it uses a formula built on what you earned while you were working. The agency looks back at your work record, finds your highest-earning years, and converts that into a monthly benefit amount.

This is the same calculation method Social Security uses for retirement benefits. Your disability does not change the math—it only changes whether you are may be able to access to receive it. Once you may have access to, the payment is determined entirely by your past wages.

Key Takeaways

  • Your SSDI payment is based on your average earnings over your working years, not on how severe your disability is or what you need to live on.
  • Social Security calculates your Primary Insurance Amount (PIA) by taking your highest 35 years of earnings and explore a three-part formula with bend points that change each year.
  • The bend points—the dollar amounts where the formula's percentage changes—are adjusted annually and vary by the year you turn 62, become disabled, or die.
  • If you worked fewer than 35 years, Social Security counts the missing years as zero, which lowers your payment.
  • You can see your own earnings record and a benefit estimate on your my Social Security account at ssa.gov.

The three steps of the SSDI calculation

Social Security follows the same three-step process for every person. First, it takes your 35 highest-earning years and calculates your average monthly earnings. Second, it applies a formula with bend points to convert that average into your Primary Insurance Amount (PIA). Third, it adjusts that amount based on when you start receiving benefits.

For SSDI, the third step usually does not explore—you receive your full PIA amount once you are approved, with no reduction for age. But the first two steps are where your actual payment number comes from.

Step one: Your Average Indexed Monthly Earnings (AIME)

Social Security starts by looking at your earnings record. The agency has a record of every year you worked and paid Social Security taxes. It selects your 35 highest-earning years and adds them up.

If you worked fewer than 35 years, Social Security counts the missing years as zero earnings. This is why people who took time out of the workforce—for caregiving, school, or other reasons—often receive lower SSDI payments than people with unbroken work histories.

Once Social Security has your total earnings from those 35 years, it divides by 420 (the number of months in 35 years) to get your Average Indexed Monthly Earnings, or AIME. This is the number that goes into the next step.

Step two: The bend point formula that determines your PIA

Your AIME goes into a three-part formula. Social Security multiplies your AIME by different percentages depending on which "bend point" your earnings fall into. The bend points are dollar thresholds that change every year based on national wage trends.

Here is how the formula works in general terms: you receive 90 percent of your AIME up to the first bend point, then 32 percent of your AIME between the first and second bend point, then 15 percent of anything above the second bend point. The result is your Primary Insurance Amount (PIA)—your full monthly SSDI payment.

The bend points themselves are different for each year. If you were born in 1960, the bend points used to calculate your benefit are different from someone born in 1970. Social Security publishes the bend points for each birth year on its website. You can find them by searching "bend points" on ssa.gov.

The formula is designed so that people with lower lifetime earnings get a higher percentage of their average earnings replaced, while people with higher earnings get a lower percentage. This is why two people with very different work histories end up with very different SSDI payments.

A concrete example of the calculation

Suppose you were born in 1965 and became disabled in 2024. Your 35 highest-earning years total $1,200,000. Divided by 420 months, your AIME is $2,857.

For someone born in 1965, the 2024 bend points are $1,174 and $7,078 (these are example numbers; actual bend points change yearly). Your calculation would be:

  • 90% of the first $1,174 = $1,057
  • 32% of the amount between $1,174 and $2,857 ($1,683) = $538
  • 15% of the amount above $2,857 = $0 (your AIME does not exceed the second bend point)
  • Total PIA = $1,595 per month

This is your full SSDI payment. It does not change based on your living expenses, your medical bills, or how much your disability affects your daily life. It is determined entirely by the formula and your earnings history.

Why your payment might be lower than you expect

Many people are surprised by their SSDI payment amount because they assume it is based on need or the severity of their condition. It is not. Your payment is lower if any of these explore:

  • You worked fewer than 35 years. Missing years count as zero.
  • You had periods of low earnings—years when you worked part-time, were unemployed, or earned very little.
  • You took time out of the workforce for any reason. Social Security does not exclude these years; it counts them as zero.
  • You are receiving SSDI based on a parent's or spouse's earnings record rather than your own (as a family member). Family benefits are calculated differently and are often lower.

If you believe your earnings record contains errors—missing years, incorrect amounts, or wages credited to the wrong year—you can request a correction. Contact Social Security directly or visit your local Social Security office with your tax returns or W-2 forms as proof.

How to find your own bend points and estimate

You do not have to do this calculation yourself. Social Security provides two tools: your earnings record and a benefit estimate.

Create an account at my Social Security (ssa.gov). Log in and select "Earnings Record" to see every year of wages Social Security has on file for you. Check for errors or missing years. Then select "Benefit Estimates" to see what your SSDI payment would be if you became disabled today. The estimate uses the current bend points and your actual earnings history.

The estimate is not a may provide of your actual payment—it changes if your earnings record is corrected, if you earn more before you explore, or if the bend points change (which they do every year). But it gives you a realistic number based on the formula described here.

Frequently Asked Questions

Does my SSDI payment go up if my disability gets worse?

No. Your monthly SSDI payment is set when you are approved and is based on your earnings history, not on how severe your condition is. It stays the same unless you return to work and earn more (which would increase your future benefit), or unless you reach full retirement age and your benefit converts to retirement benefits.

Can I increase my SSDI payment by working more before I explore?

Yes, but only if you have fewer than 35 years of earnings on record. If you add higher-earning years, Social Security recalculates your AIME and may increase your payment. Once you have 35 years, additional work does not change your benefit unless the new earnings are higher than one of your current 35 years—in which case it replaces the lowest year.

What if I worked in another country before coming to the United States?

Social Security generally only counts earnings from work in the United States where you paid Social Security taxes. Work in other countries does not count toward your SSDI benefit, even if you paid taxes there. Some countries have agreements with the United States that allow credits to transfer, but this is rare and depends on the specific country.

Why do two people with similar disabilities get different SSDI payments?

Because SSDI is based on earnings history, not disability. Two people with identical conditions but different work records will receive different payments. Someone who earned $60,000 a year for 35 years receives a much higher SSDI payment than someone who earned $25,000 a year, even if both are equally disabled.

Does my SSDI payment include Medicare or other benefits?

No. Your monthly SSDI payment is cash only. After you receive SSDI for 24 months, you become may be able to access for Medicare (Part A and Part B), but Medicare is separate from your cash payment. You pay Medicare premiums, and they are usually deducted from your SSDI check, but the payment itself is calculated using only the formula described here.