Medicare Eligibility: Who Qualifies, and When

Who qualifies

Medicare is the federal health insurance program, and you are generally eligible if you are a U.S. citizen, or a lawful permanent resident who has lived here for at least 5 years in a row, and one of four things is true. Collecting retirement benefits is not one of them: plenty of people keep working and still qualify at 65.

• You are 65 or older: The route most people take.
• You have had disability benefits for 24 months: Social Security disability or certain Railroad Retirement benefits.
• You have end-stage renal disease: Permanent kidney failure needing dialysis or a transplant, at any age.
• You have ALS: Lou Gehrig's disease. Coverage starts the same month your disability benefits do, with no waiting period.

Qualifying at 65

Eligibility at 65 works one of two ways. If you already receive Social Security or Railroad Retirement benefits, you are enrolled in Parts A and B automatically and coverage starts on the first day of the month you turn 65. If you are not collecting benefits yet, nobody signs you up and you need to sign up yourself, during a 7-month Initial Enrollment Period that opens 3 months before your birthday month and closes 3 months after it.

Qualifying before 65

Disability is the other common route. After 24 months of Social Security Disability Insurance you are enrolled automatically, and the same applies to certain Railroad Retirement benefits. The 24 months count from your first month of disability benefits, not from the date your condition began, which is usually earlier and is the part people get wrong. Your card arrives about 3 months before coverage starts.

Kidney failure and ALS work differently

Both bypass the usual age rule, but in opposite ways administratively. With end-stage renal disease you qualify at any age if you or a spouse have enough work history, but you are never enrolled automatically: you have to apply. Coverage usually begins in the fourth month of dialysis, and sooner if you train for home dialysis or have a transplant. With ALS there is no 24-month wait at all, and enrollment is automatic alongside your disability benefits.

Work history decides what Part A costs

Part A is hospital insurance, and for most people it is free. You pay no premium if you or your spouse worked and paid Medicare taxes for at least 40 quarters, roughly 10 years. With fewer quarters you can still buy it: in 2026 that is $311 a month with 30 to 39 quarters, or $565 a month with fewer than 30. Part B is different. Everyone pays a premium for it, $202.90 as the standard amount, with higher earners paying more through IRMAA. If your income is limited, there is help with Medicare costs: Medicaid or a Medicare Savings Program may cover that premium for you.

• A spouse's record counts: You can qualify on a current, former or deceased spouse's work history. After a divorce it generally requires a marriage that lasted at least 10 years.
• Government service can differ: Some federal, state and local workers paid Medicare taxes under different rules. Check your record with Social Security rather than assuming.
• Never worked at all: You can still buy Part A, though you have to take Part B as well.

When you can actually enroll

When You Can Enroll is a different question from whether you qualify, and the gap between them is where people lose money. Four windows exist, only two of them get you onto Medicare for the first time, and if you are still working with employer coverage one of them is yours by right.

• Initial Enrollment Period: Your 7-month window around turning 65. Sign up early in it to avoid a gap.
• Special Enrollment Period: 8 months from when coverage through current employment ends. This is the penalty-free way to delay.
• General Enrollment Period: January 1 to March 31 for anyone who missed out. Coverage starts the following month, usually with a penalty attached.
• Open Enrollment is not for signing up: October 15 to December 7 only lets people who already have Medicare change plans for January 1.

The coverage that does not let you delay

Only health coverage based on CURRENT employment lets you put off Part B without a penalty. COBRA does not count, and neither does retiree coverage or a plan from the Affordable Care Act Marketplace. If you lean on COBRA after a job ends, your 8-month window has already started ticking from the end of the job, not the end of COBRA, and waiting it out is how people arrive at a permanent surcharge.

What the penalties cost

Late Enrollment Penalties are the cost of getting this wrong. Miss Part B when you are first eligible without qualifying job coverage and your premium rises 10% for every full 12 months you could have had it, for as long as you stay enrolled. Part D runs on its own clock: go 63 days or more without Part D or other creditable drug coverage and a surcharge is added to that premium too.

Then you choose how to receive it

Your Coverage Choices open up once you qualify. Keep Original Medicare and add Medigap for your share of the costs plus a Medicare Part D plan for drugs, or take a Medicare Advantage plan from a private insurer, which bundles hospital and medical care and usually drugs into one plan. Either way you need Parts A and B first.

Situations worth checking before you assume

A few cases catch people out, and all of them are easier to sort out before your window opens than after.

• Living abroad: Medicare generally does not pay for care outside the U.S. Plan your enrollment if you split your time.
• Incarceration: Medicare generally does not pay for care while you are in prison.
• Still on a Marketplace plan: Once you are eligible for Medicare you should normally enroll and end the Marketplace coverage.
• Checking your own record: Social Security at 1-800-772-1213, or the Railroad Retirement Board if you worked for a railroad.

Common questions

More in Medicare 101

• Turning 65: Your complete guide to starting Medicare
• How to Enroll in Medicare, Step by Step
• Medicare and Working Past 65: When to Enroll and What to Keep
• The Parts of Medicare, Explained: A, B, C and D
• Medicare Enrollment Periods: Every Window Explained
• Medicare Late Enrollment Penalties, and How to Avoid Them
• Medicare Costs: What You'll Actually Pay
• Medicare Advantage vs. Medicare Supplement: How to Choose
• Medicare Prescription Drug Coverage: Where It Comes From and How It Works