When you apply for Social Security disability benefits, the Social Security Administration will assess your situation to determine if you can do substantial gainful activity.
Part of qualifying for benefits is the requirement that you are unable to do SGA. But it helps if you understand what SGA is and how the SSA calculates it.
SGA is anything you do to earn money. It does not have to be a full-time job with an employer. Anything you do that helps you earn an income falls under SGA, and the SSA will count it as your income. In addition, if you do something that could earn you money even if you do not earn money for it, the SSA will consider that SGA.
SGA is important because part of the requirements to get disability benefits is proving you are unable to earn a living. If your activities do or could earn you enough money, then you fail the SGA requirement of qualifying for benefits. The limit on how much you can earn changes each year according to the cost of living. But you can generally expect it to be a low threshold.
Keep in mind that anything you do could become SGA. The SSA is very strict about ensuring that anyone receiving disability benefits is really disabled to the point that he or she cannot make money to earn a living. These benefits have one of the strictest qualification thresholds to prevent abuse.
SGA is one of the reasons why getting disability benefits is often difficult. Many people have to apply multiple times before they receive approval to get benefits.