Old-Age and Survivors Insurance (OASI) is the core part of Social Security that pays monthly benefits to retired workers, their families, and survivors of deceased workers. It is often discussed alongside Hospital Insurance (HI), the health coverage component better known as Medicare Part A. Together, these two programs form the financial safety net most Americans rely on after age 65, funded through the payroll taxes withheld from every paycheck.
How OASI and Hospital Insurance Work Together
OASI and HI are separate trust funds that serve different purposes but share the same funding mechanism. OASI provides cash benefits: monthly retirement checks and payments to qualifying family members or survivors. Hospital Insurance, or Medicare Part A, covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health services. When people refer to “old age and survivors health insurance,” they’re typically talking about the combination of these two programs.
You don’t choose one or the other. If you’ve worked long enough to qualify for Social Security retirement benefits, you’re generally enrolled in Medicare Part A automatically when you turn 65. The cash income from OASI and the health coverage from Medicare Part A together form the baseline of financial and medical security in retirement.
How These Programs Are Funded
Both programs are paid for through FICA taxes, the deductions you see on every pay stub. The Social Security portion (which funds OASI and disability insurance) is 6.2% of your wages, matched by another 6.2% from your employer, for a combined 12.4%. The Medicare portion is 1.45% from you and 1.45% from your employer, totaling 2.9%. If you earn more than $200,000 in a year, an additional 0.9% Medicare tax applies to wages above that threshold, with no employer match.
There is a cap on how much of your income is subject to Social Security tax. For 2026, that cap is $184,500. Any earnings above that amount aren’t taxed for Social Security purposes. Medicare taxes, by contrast, have no income cap.
Who Qualifies for Benefits
To qualify for OASI retirement benefits, you need 40 Social Security credits, which works out to roughly 10 years of work. You earn up to four credits per year based on your earnings. Once you hit 40, you’re eligible for retirement benefits and premium-free Medicare Part A.
Survivor benefits have more flexible requirements. The number of credits the deceased worker needed depends on how old they were at death. Younger workers need fewer credits, though no one needs more than 40. A special rule also exists for families with young children: if a worker earned just six credits in the three years before death, their children and the spouse caring for those children can still receive benefits.
Survivors Who Can Receive Benefits
Spouses, ex-spouses, children, and dependent parents of a deceased worker may all qualify. For a surviving spouse, the general requirements are being age 60 or older (or 50 to 59 with a disability), having been married at least nine months before the death, and not having remarried before age 60. Ex-spouses who were married to the worker for at least 10 years can also qualify under similar rules.
Children are eligible if they are unmarried and either age 17 or younger, 18 to 19 and still in school full time, or any age if they developed a disability before turning 22. A surviving spouse of any age can also receive benefits if they are caring for the deceased worker’s child.
What Medicare Part A Covers
The health insurance side of this equation, Medicare Part A, covers the costliest types of medical care. Inpatient hospital stays are the primary coverage, including time spent in critical access hospitals. Part A also pays for stays in skilled nursing facilities after a qualifying hospital admission, hospice care for people with terminal illnesses, and certain home health services.
Part A does not cover routine doctor visits, outpatient procedures, or prescription drugs. Those fall under Medicare Parts B and D, which require separate premiums. But for workers who earned their 40 credits, Part A itself comes with no monthly premium, making it one of the most valuable benefits tied to a working career.
Full Retirement Age and Benefit Adjustments
You can start collecting OASI retirement benefits as early as age 62, but your monthly payment will be permanently reduced. Full retirement age falls between 66 and 67 depending on your birth year. Waiting until 70 increases your benefit further.
Benefits are adjusted each year to keep pace with inflation through a cost-of-living adjustment (COLA). For 2026, Social Security announced a 2.8% increase, which translates to roughly $56 more per month for the average retiree. The 2025 COLA was 2.5%. Over the past decade, the annual adjustment has averaged about 3.1%. These increases apply to all OASI and survivor benefits and take effect in January.
Financial Outlook for Both Trust Funds
Both the OASI and HI trust funds face long-term funding gaps, though their timelines differ. According to the 2024 annual trustees’ report, the OASI trust fund can pay full benefits until 2033. After that, incoming payroll taxes would still cover 79% of scheduled benefits. By 2098, that share drops to 69%.
The Hospital Insurance trust fund is in slightly better shape. It can pay full benefits until 2036, five years later than previously projected. After depletion, continuing tax revenue would cover 89% of scheduled benefits, and projections show it could still pay roughly 100% by 2098. At the end of 2023, the OASI trust fund held about $2.6 trillion in reserves, while the HI fund held roughly $209 billion.
These projections don’t mean benefits will vanish. They mean that without legislative changes, benefits could be reduced to match the revenue coming in. Congress has adjusted the programs before, and any future changes would likely involve some combination of tax increases, benefit modifications, or changes to eligibility ages.
How to Apply for Survivor Benefits
Survivor benefits are not automatic. You need to apply by calling the Social Security Administration at 1-800-772-1213 or visiting a local office. Scheduling an appointment ahead of time can reduce wait times, but walk-ins are accepted.
Documents you may need include proof of the worker’s death, your birth certificate, proof of citizenship or legal residency, your marriage certificate (or final divorce decree for ex-spouses), and recent W-2 forms or self-employment tax returns. If you’re applying for disability-related survivor benefits, additional medical forms will be required. The Social Security Administration accepts photocopies of tax documents and medical records but generally needs to see originals of birth certificates and similar documents.
If you’re approaching age 65 when you apply, you’ll also be asked whether you want to enroll in Medicare Part B, the outpatient coverage that carries a monthly premium. Don’t delay filing because you’re missing paperwork. The SSA will help you gather what you need.