How SSDI Benefits Are Calculated: The Complete 2026 Guide

If you're applying for Social Security Disability Insurance (SSDI), one of the first questions you'll have is: how much will my monthly benefit be? The answer depends on a specific formula the Social Security Administration (SSA) uses — one that most applicants have never seen and that insurance adjusters and disability attorneys know inside and out.

The SSA's Core Formula: AIME and PIA

Your SSDI monthly benefit is ultimately determined by two numbers: your Average Indexed Monthly Earnings (AIME) and your Primary Insurance Amount (PIA). Here's what each means:

Step 1: Calculate Your AIME

The SSA starts by looking at your complete earnings history — every year you paid Social Security taxes. They take your highest 35 years of earnings (indexed for inflation to today's dollars), add them up, and divide by 420 months (35 years × 12 months). The result is your Average Indexed Monthly Earnings, or AIME.

If you worked fewer than 35 years, the SSA fills the missing years with zeros — which lowers your AIME and therefore your benefit. This is why it's important to work as many years as possible before applying.

Step 2: Apply the PIA Bend Point Formula

The SSA then applies a progressive formula to your AIME using "bend points" — threshold values that change each year. For 2026, the formula is:

The result — rounded down to the nearest $0.10 — is your Primary Insurance Amount (PIA), which is your base monthly SSDI benefit.

A Concrete Example

Say your AIME is $3,500/month. The PIA calculation would be:

• 90% × $1,226 = $1,103.40
• 32% × ($3,500 − $1,226) = 32% × $2,274 = $727.68
• 15% × $0 (AIME is below $7,391) = $0
• Total PIA = $1,831.08/month

Key Factors That Affect Your Benefit

Years of Work History

As mentioned, fewer than 35 years of earnings means zeros in the calculation — directly reducing your benefit. Every additional year you work replaces a zero-year, which increases your AIME.

COLA Adjustments

Benefits increase annually based on the Cost of Living Adjustment (COLA). The 2026 COLA was 2.5%. This means your benefit grows slightly every year to keep pace with inflation.

The Workers' Comp Offset

If you receive workers' compensation or other public disability benefits, your SSDI may be reduced so that the combined amount doesn't exceed 80% of your pre-disability earnings. This is called the workers' comp offset and surprises many claimants.

Dependents' Benefits

Your spouse and children may be eligible for additional benefits based on your SSDI record — up to 50% of your PIA per eligible family member, subject to a family maximum.

SSI vs SSDI: A Different Calculation

If you're applying for Supplemental Security Income (SSI) instead of SSDI, the calculation is completely different. SSI is need-based, not earnings-based. The 2026 federal SSI maximum is $967/month for an individual and $1,450/month for a couple. Your actual benefit is reduced by any countable income you have. Some states add a supplement on top of the federal amount.

Step-by-Step: Estimating Your Benefit

1. 1

   Get your Social Security Statement

   Create a free my Social Security account at ssa.gov. Your statement shows your estimated benefit at various ages and your full earnings record.

2. 2

   Calculate your AIME

   Take your highest 35 years of earnings (adjusted for inflation), add them up, and divide by 420 months. Use your Social Security statement as a reference.

3. 3

   Apply the 2026 bend point formula

   Use the formula above: 90% of the first $1,226, 32% of the next $6,165, and 15% of anything above $7,391.

4. 4

   Check for offsets

   If you receive workers' comp or other public disability benefits, your SSDI may be reduced. A disability attorney can help you calculate this.

5. 5

   Consult an attorney

   A disability attorney reviews your full situation — work history, medical records, and potential offsets — to give you an accurate picture of your claim.