There are two types of federal disability benefits: Social Security Disability Insurance and Supplemental Security Income.
SSDI is available for people who have a substantial work history and is based on an applicant's lifetime average earnings and Social Security contributions. The higher the earnings and contributions, the larger the monthly benefit.
SSI is available for people with few assets and a limited income or work history. SSI benefits are lower than those provided by SSDI, but some states augment the flat federal amount provided'currently $603 for a single person.