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What's the difference between SSDI and SSI?

Social Security Disability Insurance (SSDI) and Supplemental Security Income (SSI) both pay benefits to people that the Social Security Administration deems disabled.

With their similar initials and overlapping missions, the two programs can be easy to confuse — but they differ in fundamental ways. Here are some of the key distinctions.

Who qualifies

  • SSDI is available to people with physical and mental impairments severe enough to prevent them from engaging in their normal occupations or any other substantial work. The disability must be expected to last for at least 12 months or to end in death.
  • SSI is a safety net program that pays benefits to people who are disabled, usually based on the same definition used for SSDI; blind; or 65 and older. They must have very limited income and assets.

How to qualify

  • SSDI is an earned benefit. As with Social Security retirement benefits, you qualify by working and paying Social Security taxes. How long you must have worked to be eligible varies based on your age when you become disabled.

As it does for the spouses and children of retirees, Social Security can pay additional benefits to the spouses and children of disabled workers. Adults who have been disabled since childhood may qualify for SSDI on a parent's record even if they never have worked.

  • SSI is not tied to a recipient's work history. You can receive SSI if you never have worked or paid Social Security taxes. But your income and other financial resources, such as bank accounts and property, must not exceed strict caps.

In 2021, the income limit is $794 a month for an individual and $1,191 a month for a couple filing for SSI jointly. That's also the maximum federal SSI benefit payment.

The resource limit is $2,000 for an individual and $3,000 for a couple.

Not all income and assets count against the caps. For example, Social Security exempts the value of your home and about half of earnings from work, among other things.

Financing and administration

  • SSDI dates to 1956, when Social Security's rules were amended to permit benefit payments to disabled workers.

Both workers and their employers primarily bear the cost of the program through payroll taxes. Benefits are paid out of Social Security's Disability Insurance Trust Fund.

Payment amounts are based on your earnings history. In 2021, the estimated average monthly SSDI benefit is $1,277.

  • SSI is managed by the Social Security Administration, but Social Security taxes do not pay for it. Rather, SSI is paid out of general revenues that the Treasury Department collects to run the U.S. government.

Social Security was put in charge of SSI when the program was established in 1972 to replace a maze of disparate state programs that provided federally financed benefits for older, blind and disabled people in financial need. Most states offer supplemental benefits to SSI recipients on top of the federal payment.

How they're similar

The Social Security Administration generally uses the same medical criteria and the same process to determine if a disability entitles an adult to SSDI or SSI. Collecting both benefits is permitted.

The condition must be expected to last at least a year or result in death and must prevent you for doing most work.

Social Security requires considerable medical evidence to back up a disability claim for either benefit. Although you can apply online for SSDI, and in some cases for SSI, the process will include an in-person or phone interview with a Social Security representative.

[Editor’s note: Local Social Security offices are currently closed to walk-in visits due to the COVID-19 pandemic. Many Social Security services are available online and by phone. If you have a "dire need situation" regarding your benefits or need to update information attached to your Social Security number, such as your name or citizenship status, you may be able to schedule an in-person appointment. See Social Security's coronavirus page or call your local office for more information.]

Getting a decision generally takes three to five months, according to Social Security officials, but the time can vary depending on how long Social Security needs to get medical records and other relevant evidence. Military veterans and people with particular severe medical issues may qualify for expedited processing.

Keep in mind

A majority of applications for disability benefits are initially denied. If your application is rejected, you have the right to appeal, but getting a hearing can take a year or more. The Social Security Administration has a considerable backlog of cases.

Updated December 28, 2020

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