As with retirement benefits, qualification for SSDI is measured in Social Security credits.
You acquire credits for paying Social Security taxes on your work income. In 2024, you get one credit for each $1,730 you earn in such “covered” employment (or self-employment), up to a maximum of four credits per year (for $6,920 or more in earnings). The credit amount is automatically adjusted annually to reflect national wage trends.
The number of work credits you need to qualify for disability benefits depends on your age when your disability begins. Generally, you need 40 credits, 20 of which were earned in the last 10 years ending with the year your disability begins.