What is the difference between Social Security Disability Insurance (SSDI) and  Supplemental Security Income Program (SSI)?

SSDI is a government insurance program. SSI is a program to provide income to those who are disabled and poor.
You pay into SSDI through taxes on your wages, and if you become disabled, you may qualify for benefits.  You can also be considered “insured” through the  contributions from the earnings of your spouse or  parents. You don’t pay anything specifically into SSI, and you can receive SSI benefits even if you have never worked, as long as you meet Social Security’s disability criteria and income criteria. Children can qualify for SSI.
SSDI payments come from a dedicated trust fund. SSI payments are derived from general tax revenues.
The two qualifications for SSDI are 1) you must be disabled by Social Security’s criteria, and 2) you must have paid enough into the system within the past 10 years (known as quarters of coverage).  A quarter of coverage in 2004 is $1200.  No matter how high your earnings may be, you can only earn four quarters in a year.  To be fully insured you need at least 20 quarters of coverage in the last 10 years (although this can be less if you are a younger worker).  The minimum number of quarters needed is six and the maximum number is 40. The two qualifications for SSI are 1) you must be disabled by Social Security’s criteria, and 2) you must meet Social Security’s criteria for limited income and resources.
Your eligibility for SSDI benefits expires 10 years after you stop paying into it (usually 10 years after you stop working), unless you have already have 40 quarters of coverage. Eligibility for SSI does not expire.
If you qualify for SSDI, you receive health care benefits through Medicare. If you qualify for SSI, you receive health care benefits through Medicaid.
If you qualify for SSDI benefits, your monthly payment amount depends on your lifetime average earnings covered by Social Security.  Other income or resources do not affect your payment amount, and there are no state supplements. If you qualify for SSI benefits, your benefit amount starts with the Federal Benefit Rate (which in 2014 is $721 per month for an individual and $1082 per month for a couple), then your countable income is subtracted and a state supplement is added if there is one in your state.  (Most states, including Florida and Georgia, have a state supplement for adults.  States that do not have a state supplement for adults are Arizona, North Dakota, Mississippi, and West Virginia. Georgia also has a state supplement for children, but Florida does not.)

If you have other questions about qualifying for SSDI or SSI, please call me at 850-224-7653.  For those in my locale, I am happy to offer a free consultation.