How To Calculate Social Security Disability

Use this premium SSDI calculator to estimate your monthly disability benefit from your Average Indexed Monthly Earnings, apply a workers’ compensation or public disability offset, and project future payments with a COLA assumption. This is an educational estimate based on Social Security bend-point formulas, not an official SSA determination.

Expert Guide: How to Calculate Social Security Disability

When people search for how to calculate Social Security disability, they are usually trying to answer one practical question: “What could my monthly SSDI check be?” The answer depends on a federal formula, not on a simple percentage of your final salary. Social Security Disability Insurance, often called SSDI, is tied to your work history and the Social Security taxes you paid on covered earnings. In other words, the system looks backward at your lifetime earnings record, converts those earnings into an indexed value, averages them into a monthly figure, and then applies a benefit formula that uses bend points.

That sounds technical, but the process becomes much easier once you break it into steps. The most important concept is that Social Security does not generally look at your last paycheck and decide to replace a fixed share of it. Instead, the agency builds your benefit around your Average Indexed Monthly Earnings, also called AIME. Your AIME then flows into the formula for your Primary Insurance Amount, or PIA, which is the base monthly benefit used for SSDI and retirement calculations.

This guide walks through the calculation method, shows what the percentages mean, explains when offsets apply, and helps you avoid common mistakes. The calculator above gives you a practical estimate, while the sections below explain the logic behind the numbers in plain English.

Step 1: Understand the Difference Between SSDI and SSI

Before doing any math, make sure you are estimating the correct program. SSDI and Supplemental Security Income, or SSI, are not calculated the same way.

• SSDI is based on your covered work history and payroll tax contributions.
• SSI is a need-based program for people with limited income and resources.
• SSDI benefit amounts vary by earnings record, while SSI federal benefit rates are set by law and then adjusted.

If you are asking how to calculate Social Security disability based on what you earned over the years, you are almost certainly talking about SSDI. That is the program this calculator addresses.

Step 2: Start With Your AIME

Your AIME is the heart of the SSDI benefit formula. SSA reviews your earnings record, indexes past wages to reflect overall wage growth, and then averages the highest applicable years of earnings into a monthly number. That number is your Average Indexed Monthly Earnings.

For most consumers, the most realistic way to get an estimate is one of these:

1. Use your my Social Security account to review your earnings record.
2. Use the official SSA calculators if you want a government-generated estimate.
3. Use a manual estimate like this page if you already know or can approximate your AIME.

If your earnings record contains errors, your estimated SSDI amount can be off. That is why checking your Social Security statement matters. Even a few years of missing covered wages can reduce the AIME enough to change the final monthly benefit.

Why indexed earnings matter

Indexing adjusts older earnings to better reflect current wage levels. Without indexing, a person who earned solid wages twenty years ago would look artificially underpaid in today’s dollars. SSA uses indexing to create a fairer comparison across a full working career.

Step 3: Apply the PIA Formula

Once you have the AIME, the next stage is the Primary Insurance Amount formula. This formula applies three replacement rates to slices of the AIME. Those slices are separated by annual bend points. The structure is progressive, which means lower portions of earnings get replaced at a higher rate than higher portions.

The standard formula is:

• 90% of the first bend-point portion of AIME
• 32% of the amount between the first and second bend points
• 15% of the amount above the second bend point

That formula does not mean everyone gets 90% of income. It only means the first layer of AIME receives the 90% factor. The next layer gets 32%, and only the highest layer gets 15%.

Formula Year	First Bend Point	Second Bend Point	Formula Applied to AIME
2024	$1,174	$7,078	90% of first $1,174, plus 32% of AIME from $1,174 to $7,078, plus 15% above $7,078
2025	$1,226	$7,391	90% of first $1,226, plus 32% of AIME from $1,226 to $7,391, plus 15% above $7,391

Example of the SSDI formula

Suppose your AIME is $4,500 and you use the 2024 bend points:

1. First tier: 90% of $1,174 = $1,056.60
2. Second tier: 32% of ($4,500 – $1,174) = 32% of $3,326 = $1,064.32
3. Third tier: none, because AIME does not exceed $7,078

Estimated PIA: $1,056.60 + $1,064.32 = $2,120.92 before any applicable reductions, rounding conventions, or offsets.

That is why two people with different salaries may not see benefits rise in direct proportion to pay. The progressive formula replaces more of lower earnings and less of higher earnings.

Step 4: Check for Workers’ Compensation or Public Disability Offsets

One of the biggest areas of confusion in learning how to calculate Social Security disability is the offset rule. If you receive SSDI and also receive workers’ compensation or certain public disability benefits, your SSDI payment may be reduced. The basic principle is that the combined amount generally cannot exceed 80% of your Average Current Earnings, often abbreviated ACE.

In practical terms:

• Calculate your SSDI base amount using the PIA formula.
• Find 80% of your Average Current Earnings.
• Add your workers’ compensation or public disability payment to your SSDI estimate.
• If the total is above the 80% cap, SSA may reduce SSDI so the combined amount fits under the limit.

Example: If your ACE is $6,000, then 80% is $4,800. If your estimated SSDI is $2,120.92 and workers’ compensation is $3,000, the total would be $5,120.92. That exceeds the cap by $320.92, so the payable SSDI may be reduced by about that amount, leaving an estimated SSDI payment of roughly $1,800.00.

Not every disability claimant has an offset, but when one applies it can materially change the monthly check. That is why this calculator asks for both ACE and any workers’ compensation or public disability amount.

Step 5: Consider Cost-of-Living Adjustments

After your initial benefit is established, SSDI benefits may rise over time through cost-of-living adjustments, commonly called COLAs. These annual increases do not change the basic PIA formula itself for your original entitlement in the same way as a fresh initial determination, but they do affect what you may actually receive in future years.

For planning purposes, it is reasonable to model a future COLA assumption, such as 2% or 2.5% annually. The calculator above lets you project a number of years using your own assumed COLA. That projection is only a planning tool. Actual SSA COLAs are announced officially and can be higher, lower, or zero depending on inflation measures.

Key Social Security Disability Figures People Often Mix Up

Not every number associated with disability benefits affects the payment formula directly. Some figures are eligibility thresholds rather than benefit formulas. The table below highlights several frequently searched numbers.

Item	2024 Figure	2025 Figure	Why It Matters
Substantial Gainful Activity, non-blind	$1,550 per month	$1,620 per month	Used in disability eligibility screening, not as the SSDI benefit formula itself.
Substantial Gainful Activity, blind	$2,590 per month	$2,700 per month	Higher threshold for statutory blindness cases.
PIA first bend point	$1,174	$1,226	Defines the first, most heavily replaced slice of AIME.
PIA second bend point	$7,078	$7,391	Defines where the 32% tier ends and the 15% tier begins.

How to Manually Calculate SSDI in 5 Clear Steps

1. Confirm you are estimating SSDI, not SSI. SSDI depends on your work record.
2. Determine your AIME. Use your Social Security earnings record or SSA estimate tools.
3. Choose the correct bend-point year. Initial benefit formulas use annual bend points published by SSA.
4. Apply the PIA percentages. 90% to the first tier, 32% to the middle tier, and 15% to the top tier.
5. Test for offsets. If workers’ compensation or public disability benefits apply, compare the total against 80% of ACE.

If you follow those five steps carefully, you can create a reliable planning estimate of Social Security disability benefits. An official determination, however, will still depend on SSA’s records, rounding conventions, entitlement dates, family benefits, any offset rules, and agency review of your claim.

Common Mistakes When Estimating Disability Benefits

Using current salary instead of AIME

This is the most common error. AIME is not the same thing as your current monthly pay. Your benefit is based on a broader earnings history, not just your most recent job.

Ignoring missing earnings on your SSA record

If your Social Security statement is missing wages, your estimate may be too low. Review your record before relying on any manual calculation.

Forgetting the offset rule

People receiving workers’ compensation sometimes estimate their SSDI correctly but then forget that the payable amount may still be reduced. If you have concurrent benefits, always test for an offset.

Assuming SGA thresholds equal benefit amounts

The substantial gainful activity threshold is an eligibility measure. It does not tell you what your SSDI check will be. It simply helps SSA assess whether work activity may be considered substantial.

What About Spouses, Children, and Family Maximum Benefits?

In some cases, eligible dependents can receive auxiliary benefits on a disabled worker’s record. That introduces another layer of calculations, including family maximum rules. Because family maximum computations can differ from the simple worker-only estimate, the calculator above focuses on the disabled worker’s monthly amount. If you are estimating total household benefits, you may need a more detailed review of family maximum limits and dependent eligibility.

When You Should Use Official Government Sources

Educational calculators are excellent for planning, but you should verify important decisions with official sources. For example, if you are deciding whether to appeal a denial, compare workers’ compensation settlement language, or estimate the financial impact of an onset date, always check SSA materials or seek professional guidance.

Useful official references include:

• Social Security Administration Disability Benefits
• SSA Primary Insurance Amount Formula and Bend Points
• SSA Substantial Gainful Activity Figures

Bottom Line

If you want to know how to calculate Social Security disability, the shortest accurate answer is this: find your AIME, apply the annual PIA formula with the correct bend points, and then test whether any workers’ compensation or public disability offset reduces the payable amount. After that, you can project future payments using likely COLAs for planning purposes.

The calculator on this page is designed to make that process straightforward. Enter your AIME, choose the formula year, add any workers’ compensation or public disability amount, and let the calculator estimate your PIA and projected monthly payment. For the most accurate result, compare your inputs against your official Social Security earnings record and SSA publications.

This page provides an educational estimate only. Actual SSDI amounts can differ because of SSA rounding rules, date of entitlement, freeze periods, family maximum calculations, Medicare premium deductions where applicable, overpayment recovery, and offsets not modeled here.