How Do We Define Disability?

Our Definition of Disability

To meet our definition of disability, you must not be able to engage in any substantial gainful activity (SGA) because of a medically-determinable physical or mental impairment(s):

  • That is expected to result in death, or
  • That has lasted or is expected to last for a continuous period of at least 12 months.


There is a separate definition of disability for children (under age 18) who are applying for the Supplemental Security Income (SSI) program. A disabled child also qualifies for the SSI employment supports described later in the Red Book.

What is Substantial Gainful Activity (SGA)?

We use the term “substantial gainful activity” to describe a level of work activity and earnings.

Work is “substantial” if it involves doing significant physical or mental activities or a combination of both. For work activity to be substantial, it does not need to be performed on a full-time basis. Work activity performed on a part-time basis may also be SGA.

“Gainful” work activity is:

  • Work performed for pay or profit; or
  • Work of a nature generally performed for pay or profit; or
  • Work intended for profit, whether or not a profit is realized.

We use SGA as one of the factors to decide if you are eligible for disability benefits. If you receive Social Security Disability Insurance (SSDI) benefits, we use SGA to decide if your eligibility for benefits continues after you return to work and complete your Trial Work Period (TWP) (see TRIAL WORK PERIOD). If you receive SSI benefits based on disability, we apply different standards to determine if your eligibility for benefits should continue. For details on how we calculate SSI benefits, see SSI ONLY EMPLOYMENT SUPPORTS.

We do not use SGA as a factor to determine initial eligibility for SSI benefits if you are blind.

How Do We Evaluate Your Activity for SGA Purposes?

We generally use earnings guidelines to evaluate whether your work activity is SGA.

The amount of monthly earnings we consider to be SGA depends on the nature of your disability. The Social Security Act specifies a higher SGA amount for persons who meet the definition of blindness described by the law. For details on our rules about earnings and blindness, see SPECIAL RULES FOR PERSONS WHO ARE BLIND.

If your impairment is anything other than blindness, earnings averaging over $1,180 a month (for the year 2018) generally demonstrate SGA. If you are blind, earnings averaging over $1,970 a month ( for the year 2018) generally demonstrate SGA for SSDI. We usually adjust these amounts every year based on increases in the national average wage index.

What If You Are Self-employed?

If you are self-employed and your disability is not blindness, the way we evaluate your work activity for SGA purposes will depend on whether we evaluate your work activity before or after you have received SSDI benefits for 24 months and the purpose of the evaluation. We will evaluate your work under The Three Tests or the Countable Income Test to determine if your work activity is SGA, depending on when you worked.

The Three Tests:

We apply three tests to evaluate your work activity when you initially apply for SSDI and before you have received SSDI benefits for 24 months. We will also use the three tests to evaluate your work activity during the re-entitlement period to determine if we can reinstate your benefits in the Extended Period of Eligibility (EPE) (see EXTENDED PERIOD OF ELIGIBILITY). Your self-employment work activity is SGA if:

  • You render significant services to the business, and you had average monthly earnings over the SGA level ($1,180 in 2018); or
  • Your work is comparable to the work of persons without disability in your community engaged in the same or similar businesses; or
  • Your work is worth more than the SGA level earnings in terms of its effects on the business or when compared to what you would have to pay an employee to do the work.

The Countable Income Test:

We apply the countable income test if you have received SSDI benefits for at least 24 months. We will only use the countable income test to determine whether you have engaged in SGA and if your disability has ended as a result of that SGA.

We will compare your countable earnings to the SGA earnings guidelines. If your monthly countable earnings average more than $1,180 (in 2018), we will determine that your work is SGA unless there is evidence that you are not rendering significant services in the month. If your monthly countable earnings average less than $1,180, we will decide that your work is not SGA.

If you are self-employed and your disability is blindness, we decide SGA based on whether you have received a substantial income from the business and rendered significant services to the business. We make this determination using your countable earnings. We also use your countable earnings to determine whether your work is SGA and we can reinstate benefits during the EPE (see EXTENDED PERIOD OF ELIGIBILITY).

If you are self-employed, your disability is blindness, and you are age 55 or older, special rules apply. If your earnings demonstrate SGA but your work requires a lower level of skill and ability than the work you did before age 55, or when you became blind, whichever is later, we will suspend, not terminate, your benefits. Your eligibility for SSDI benefits continues indefinitely, and we pay your benefits for any months’ earnings falling below SGA.