SSDI vs SSI: Eligibility, Differences & How to Apply

The Social Security Administration (SSA) runs two disability programs with the same medical test and very different financial rules. SSDI is insurance you paid for through payroll tax. SSI is a needs-based benefit for people with little income and few assets. Many people qualify for one, some for both, and the application for each starts in the same place: a Social Security office, the 1-800 line, or ssa.gov.

SSDI and SSI side by side

	SSDI (Disability Insurance)	SSI (Supplemental Security Income)
Funded by	Social Security payroll taxes	General federal revenue
Who qualifies	Workers with enough recent work credits who become disabled	People aged 65+, blind or disabled with limited income and resources
Work history required	Yes, generally 40 credits with 20 earned in the last 10 years; fewer if under 31	None
Income and asset limits	None for eligibility (but substantial work ends benefits)	Yes: countable resources of $2,000 (individual) or $3,000 (couple); income reduces the payment
Monthly amount	Based on your lifetime earnings; the average and maximum are updated each year	A federal base rate set each year, reduced by countable income; some states add a supplement
Waiting period	Five full months after disability onset	None; payments can start the month after application
Health coverage	Medicare after 24 months of entitlement	Medicaid, in most states automatically
Family benefits	Spouse and children may receive auxiliary benefits	None
Back pay	Up to 12 months before the application date	Only back to the application month

SSA updates the dollar figures every January; the current numbers are published at ssa.gov and are not repeated here so they do not go stale.

The definition of disability (same for both programs)

For adults, SSA pays only for total disability: a medically determinable physical or mental condition that prevents substantial gainful activity (SGA) and has lasted, or is expected to last, at least 12 months or to result in death. There is no partial or short-term disability benefit.

SSA decides using a five-step sequence:

Are you working above the SGA level? If your earnings exceed the monthly SGA amount (higher for blind applicants), the claim is denied at this step.
Is your condition severe? It must significantly limit basic work activities.
Does it meet or equal a listing? SSA's "Blue Book" lists conditions with specific medical criteria. Meeting a listing approves the claim.
Can you do your past work? If you can still perform any job you held in the last 15 years, the claim is denied.
Can you do any other work? Considering age, education and skills, SSA decides whether other jobs exist that you could do. Rules are more favorable from age 50 and again from 55.

Steps 3 to 5 are decided by your state's Disability Determination Services (DDS) using medical records, not by the field office. The field office handles the non-medical part: work credits for SSDI, income and resources for SSI.

SSDI in detail

Work credits. You earn up to four credits a year. Most adults need 40 credits, 20 of them in the ten years before disability began. Under 31, the requirement is proportionally lower (for example, six credits in the three years before onset if you are under 24).

Five-month waiting period. SSDI pays nothing for the first five full months after the onset date. If your onset was long before you applied, the waiting period is already served and back pay can cover up to 12 months before the application.

Medicare. Starts automatically 24 months after SSDI entitlement begins (immediately for ALS and end-stage renal disease).

Working while on SSDI. A trial work period lets you test work for nine months without losing benefits, followed by an extended period of eligibility. Report all work to SSA.

SSI in detail

Who. Aged 65 or older, blind, or disabled, with limited income and resources, and a U.S. citizen or qualifying non-citizen living in the United States.

Resources. Countable assets must be at or below the limit: cash, bank accounts, stocks, a second vehicle and property other than your home. Your home, one vehicle, household goods, burial plots and certain burial funds do not count.

Income. Most income reduces the payment roughly dollar for dollar after small exclusions; earned income is counted at about half after the first $65 a month. Living in someone else's household and receiving free food or shelter can also reduce the payment.

Medicaid. In most states SSI eligibility brings automatic Medicaid; a few states run a separate application.

Children. Children under 18 can receive SSI based on their own disability and the parents' income and resources, under a separate childhood definition of disability.

The SSI application guide covers the forms and the interview.

How to apply

Online

SSDI: the full application is at ssa.gov/applyfordisability. It includes the Adult Disability Report (medical and work history). You can save and resume.
SSI: adults aged 18 to 64 can start online; SSA then calls you to finish the interview. People 65 and older, and parents applying for a child, apply by phone or at an office.

By phone

Call 1-800-772-1213 (TTY 1-800-325-0778) and ask for a disability appointment. The representative completes the application in a telephone interview, usually one to two hours.

At an office

Book first through the appointment page, then bring the documents below. Find the office with the ZIP locator. Any field office can take a disability claim; in a few metros routine card work goes elsewhere, but disability does not.

Documents and information to have ready

Social Security number and proof of age
Names, addresses, phone numbers and dates for every doctor, clinic and hospital
Medication names and dosages
Medical records you already hold; SSA requests the rest with your signed release
Work history for the past 15 years: employers, dates, duties
Last year's W-2 or tax return
Workers' compensation or other disability award letters
Bank account details for direct deposit
For SSI: bank statements, pay stubs, lease, vehicle registration, insurance policies

The full checklist is in what to bring to the Social Security office.

How long it takes

Initial decisions take several months; SSA publishes the current national average, which has been in the range of six to eight months. Claims for certain severe conditions are fast-tracked under Compassionate Allowances and can be decided in weeks. Terminal illness claims and military service members with wounds sustained on active duty also get expedited handling.

If you are denied: the appeals ladder

Most initial claims are denied; many are approved on appeal. You have 60 days from the notice to file each step.

Reconsideration: a fresh review by a different DDS examiner. File online.
Hearing before an administrative law judge. This is where approval rates are highest; medical evidence and testimony are reviewed in person, by video or by phone. Waits can be a year or more.
Appeals Council review.
Federal district court.

You can be represented at any stage. Representatives' fees are limited by law and are paid only if you win.

Frequently asked questions

Can I get SSDI and SSI at the same time?

Yes, if your SSDI amount is low enough that you still fall under the SSI income limit. SSI tops you up to the federal rate.

Is there a separate "SSI office" or "disability office"?

No. Every Social Security field office takes SSDI and SSI applications. The medical decision is made by the state DDS, which does not see the public.

Does a doctor's letter saying I am disabled get me approved?

No. SSA applies its own five-step test to the medical evidence; a supportive doctor's statement helps but does not decide the claim.

Can I work while applying?

Working above the SGA level results in denial at step one. Below it, you can work, but report the earnings.

What about short-term or partial disability?

SSA does not pay either. Some states have short-term disability insurance programs, and private policies cover partial disability.

SSDI vs SSI: Which Disability Benefit Applies to You and How to Apply