The law defines disability as the inability to engage in any substantial gainful activity (SGA) by reason of any medically determinable physical or mental impairment(s) which can be expected to result in death or which has lasted or can be expected to last for a continuous period of not less than 12 months. A person who is working full time or earning more than a certain monthly amount is ordinarily considered to be engaging in SGA. The amount of monthly earnings that are considered to be SGA increases slightly each year.
The link below shows the amounts considered to be SGA for the last 25 years. For 2020, a person is considered to be engaging in SGA if they work full time or earn more than $1,260 a month.