How Are SSDI Benefits Calculated? (2026 Formula + Calculator)

SSDI benefits are calculated by a very specific formula and here’s the thing most applicants don’t realize: your monthly benefit has nothing to do with the severity of your disability or your current financial situation. It’s based entirely on your work history and how much you paid into Social Security over the years.

Here’s exactly how the calculation works, with a calculator at the end to estimate your own benefit.

The three-stage calculation

SSA calculates your benefit in three stages: AIME, then PIA, then your monthly payment.

Stage 1: Average Indexed Monthly Earnings (AIME)

First, SSA looks at your lifetime earnings that were subject to Social Security taxes. They index those past earnings for inflation — so wages you earned in 1995 get adjusted using the National Average Wage Index to reflect current-day dollar equivalents. This prevents your older, lower-dollar earnings from dragging down your average.

Next, they take your highest-earning years. For workers retiring, that’s up to 35 years. For younger disabled workers, fewer years are used — SSA drops your lowest-earning years and keeps enough to cover most of your working life.

Finally, they total those indexed earnings and divide by the number of months. The result is your AIME — essentially your inflation-adjusted average monthly paycheck over your working life.

Stage 2: Primary Insurance Amount (PIA)

This is where the actual formula kicks in. Your AIME gets split into three “slices” using two threshold amounts called bend points. In 2026, the bend points are $1,286 and $7,749. Each slice is multiplied by a different percentage:

• 90% of your AIME up to $1,286
• 32% of your AIME between $1,286 and $7,749
• 15% of your AIME above $7,749

Add those three amounts together and you have your PIA (Primary Insurance Amount). That’s the foundation of your benefit.

Stage 3: Your monthly benefit

For SSDI, your monthly payment equals 100% of your PIA. There’s no reduction for claiming early (unlike retirement benefits, where claiming before your full retirement age permanently reduces the amount).

A worked example

Say your AIME comes out to $5,000/month. Here’s how the formula applies:

• 90% × $1,286 = $1,157.40
• 32% × ($5,000 − $1,286) = 32% × $3,714 = $1,188.48
• 15% × $0 (your AIME doesn’t exceed the second bend point) = $0
• PIA: $2,345.88 → that’s your monthly SSDI benefit

Try it yourself

Use the calculator below to estimate your own SSDI benefit based on your average annual income.

The calculator gives you a good ballpark, but keep in mind the actual SSA calculation uses your real earnings record indexed year-by-year. For an official estimate based on your real earnings history, create an account at ssa.gov/myaccount.

Why the formula is shaped this way

The bend-point percentages (90%/32%/15%) are deliberately progressive. Lower earners get back a much larger share of their past wages than higher earners do. Someone with an AIME of $1,000 gets $900/month (a 90% replacement rate). Someone with an AIME of $8,000 gets about $3,206/month — only about a 40% replacement rate.

The design reflects a core Social Security principle: the program is meant to be a more meaningful safety net for workers with lower lifetime earnings, who generally have fewer other resources to fall back on.

What your actual benefit might look like

In 2026, the average monthly SSDI benefit is around $1,630. But individual amounts vary widely:

• Low earners (career earnings under $30K/yr): roughly $800–$1,400/month
• Middle earners ($40K–$70K/yr): roughly $1,400–$2,400/month
• High earners (max taxable earnings for many years): up to roughly $4,000+/month

The maximum possible SSDI benefit in 2026 is approximately $4,152/month, reached only by workers who paid Social Security taxes at the maximum taxable earnings level for most of their careers.

What affects your benefit amount

Several things can change your final SSDI check:

• Years you didn’t work count as zero earnings when SSA averages — gaps pull your AIME down.
• Years of low earnings (while raising a family, in school, recovering from a prior illness) also reduce your AIME.
• Other public benefits like Workers’ Compensation or certain state disability payments can cause an “offset” that reduces your SSDI to keep combined benefits under 80% of your prior earnings.
• Returning to work under the work incentive programs doesn’t change your underlying PIA — see our breakdown of working while on SSDI for how earnings interact with your benefit.

Family benefits

If you’re approved for SSDI, certain family members may also qualify for benefits on your record — typically your spouse (if 62+ or caring for your child), and dependent children. Family benefits can add up to 50% of your PIA per eligible family member, subject to a “family maximum” cap that’s usually 150–180% of your PIA.

SSI is calculated completely differently

If you qualify for SSI instead of (or in addition to) SSDI, the math is entirely different. SSI starts from a federal benefit rate ($994/month for an individual in 2026) and then subtracts countable income dollar-for-dollar. See our guide to SSDI vs. SSI to understand which program fits your situation, and whether you might be eligible for both concurrently.

Getting your actual number

The single best way to see what SSA actually has on file for you — and what your projected benefit would be — is to create a free my Social Security account at ssa.gov/myaccount. You’ll see your year-by-year earnings record (check it for errors — missing years happen more often than you’d think) and your projected PIA based on real data.

If you’ve applied and are waiting on a decision, or you’ve been denied, how much you’ll eventually receive matters a lot — and so does whether you get approved at all. A disability attorney or advocate can review your situation, flag issues with your earnings record, and represent you through the appeals process if needed. Most offer free consultations and don’t charge unless you win.

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