SSI and SSDI are often confused because both are administered by the Social Security Administration and both require a medical disability determination. But they are funded differently, have different eligibility rules, and come with different benefits.
The Core Difference
SSDI is an insurance program funded by payroll taxes. You earn eligibility by working and paying into Social Security. SSI is a welfare program funded by general tax revenues. It is available to people with limited income and resources regardless of work history.
Side-by-Side Comparison
- Work history required: SSDI — Yes. SSI — No.
- Income and resource limits: SSDI — No (income from work may affect benefits). SSI — Yes, strict limits apply.
- Benefit amount: SSDI — Based on your earnings record (average $1,537/month in 2024). SSI — Fixed federal rate ($943/month in 2024).
- Medicare eligibility: SSDI — After 24 months of benefits. SSI — Medicaid eligibility usually begins immediately.
- Children can receive: SSDI — Only on a parent's record. SSI — Yes, based on child's own disability and family income.
Can You Receive Both?
Yes. If your SSDI benefit is low enough, you may qualify for SSI to supplement it. This is called "concurrent benefits." SSA will calculate both and pay the difference if your SSDI falls below the SSI federal benefit rate.
Which Should You Apply For?
If you have a significant work history, apply for SSDI first. If you have little or no work history, or if your SSDI benefit would be very low, apply for SSI — or both at the same time. SSA will determine which programs you qualify for based on your application.