Medicare Eligibility

Who Is Entitled to Medicare?

Medicare isn’t just for people who turn 65. There are multiple pathways to eligibility — and the rules around what you qualify for, when you must enroll, and what it costs are more nuanced than most people realize.

65+ Age-based eligibility
Under 65 Disability or ESRD
4 Parts of Medicare

Not sure if you qualify — or what to do next? We’ll walk you through it.

Four Ways to Become Eligible for Medicare

Most people qualify through age, but Medicare also covers people under 65 in specific circumstances.

1

Age 65 or Older

The most common pathway. You’re eligible for Medicare if you are 65 or older and:

A U.S. citizen, or
A legal permanent resident who has lived in the U.S. continuously for at least 5 years

You do not need to be retired or have stopped working to qualify.

2

Disability (Under 65)

You qualify for Medicare before age 65 if you have received Social Security Disability Insurance (SSDI) benefits for:

24 consecutive months — Medicare begins automatically in month 25

This applies to any qualifying disability. The 24-month waiting period begins from your first SSDI payment, not your application date.

3

End-Stage Renal Disease (ESRD)

You qualify for Medicare at any age if you have permanent kidney failure requiring:

Regular dialysis, or
A kidney transplant

Coverage typically begins the 4th month of dialysis (or sooner in some cases). There is no 24-month waiting period for ESRD.

4

ALS (Lou Gehrig’s Disease)

If you are diagnosed with Amyotrophic Lateral Sclerosis (ALS), you qualify for Medicare:

Automatically — the month your SSDI benefits begin
No 24-month waiting period

ALS is the only condition with an immediate Medicare eligibility exception — there is no waiting period of any kind.

Part A: Premium-Free vs. Premium

Most people get Part A (hospital insurance) automatically and without a monthly premium — but not everyone. Your eligibility depends on your work history.

Premium-Free Part A

$0/month

You qualify for premium-free Part A if:

You (or your spouse) paid Medicare taxes for at least 40 quarters (10 years) of work
You are 65+ and eligible for Social Security or Railroad Retirement benefits (even if you haven’t filed yet)
You are under 65 and have received SSDI for 24 months
You have ALS or ESRD

This is the most common scenario. Most Americans qualify for premium-free Part A.

Premium Part A

Up to $518/month (2025)

You can buy Part A if you don’t qualify for it for free:

You (or your spouse) have fewer than 40 quarters of Medicare tax payments
30–39 quarters: Reduced premium (approximately $285/month in 2025)
Fewer than 30 quarters: Full premium (up to $518/month in 2025)

This applies to some immigrants, people who worked in non-covered employment, and those who didn’t work long enough in the U.S.

Important: Spouse & Ex-Spouse Work History Counts

If you don’t have 40 quarters of work history, you may still qualify for premium-free Part A based on your current spouse’s or ex-spouse’s work history — as long as the marriage lasted at least 10 years and you haven’t remarried.

What Each Part of Medicare Covers

Once you’re eligible, understanding which parts of Medicare you’re entitled to — and what they cover — is the foundation for making smart coverage decisions.

A

Part A — Hospital Insurance

Covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health services.

Cost:$0/month for most people (with 40+ quarters of work history)

Most people are automatically enrolled when they turn 65 if they’re already receiving Social Security.

B

Part B — Medical Insurance

Covers doctor visits, outpatient care, preventive services, durable medical equipment, mental health services, and ambulance services.

Cost:Standard premium of $185/month in 2025 (higher earners pay more — IRMAA)

You must actively enroll in Part B unless you’re auto-enrolled through Social Security. Learn about Part B enrollment →

C

Part C — Medicare Advantage

Private plans that bundle Part A, Part B, and usually Part D together. Many include extra benefits like dental, vision, hearing, and fitness.

Requirement:Must have both Part A and Part B to enroll in a Part C plan

Optional — you choose to enroll during specific enrollment periods. Learn about Advantage plans →

D

Part D — Prescription Drug Coverage

Covers prescription medications. Available as standalone plans or built into most Medicare Advantage plans.

Cost:Premiums vary by plan ($0–$100+/month). Late enrollment carries a permanent penalty.

Optional but recommended — even if you don’t take medications now. Learn about Part D →

Working Past 65: When Must You Enroll?

If you’re still working at 65 with employer health insurance, your enrollment rules depend on the size of your employer.

Employer With 20+ Employees

Your employer insurance is your primary coverage
You can delay Part B without penalty while covered
You qualify for a Special Enrollment Period when you or your spouse stops working or loses employer coverage
Many people still enroll in Part A at 65 since it’s free
💡Exception: If you’re contributing to an HSA, enrolling in Part A can affect your ability to contribute. Review this carefully.

Employer With Fewer Than 20 Employees

⚠️Medicare becomes your primary coverage at 65
⚠️You must enroll in Part B during your IEP to avoid penalties
⚠️Your employer plan becomes secondary — it may pay little or nothing if you don’t have Medicare
⚠️Delaying enrollment can result in permanent Part B penalties

Critical distinction: COBRA, retiree coverage, VA benefits, and marketplace plans do not count as employer coverage from a large employer. These do not allow you to delay Part B without penalty.

Automatic Enrollment vs. Active Enrollment

Some people are automatically enrolled in Medicare. Others must take action to avoid coverage gaps and penalties.

Automatically Enrolled

Already receiving Social Security benefits at 65 → auto-enrolled in Part A and Part B
Receiving SSDI for 24 months → auto-enrolled in Part A and Part B in month 25
Diagnosed with ALS → auto-enrolled when SSDI benefits begin

You’ll receive your Medicare card in the mail approximately 3 months before your 65th birthday. You can decline Part B if you have qualifying employer coverage.

Must Actively Enroll

Not yet receiving Social Security at 65 → you must sign up for Part A and Part B yourself
Working past 65 with employer coverage → you must enroll during your Special Enrollment Period when coverage ends
ESRD patients → must apply through Social Security
Part D, Advantage, and Supplement plans → always require active enrollment

Missing your enrollment window can result in permanent penalties and coverage gaps. Don’t assume enrollment happens automatically.

Common Misconceptions About Medicare Eligibility

“I have to be retired to get Medicare.”
You’re eligible at 65 regardless of work status. You can be working full-time and still qualify.
“Medicare is free.”
Part A is free for most people, but Part B has a monthly premium ($185/month in 2025). You also pay deductibles, copays, and coinsurance.
“Medicare covers everything.”
Original Medicare (Parts A & B) has no out-of-pocket maximum. It doesn’t cover dental, vision, hearing, or most long-term care. Supplement or Advantage plans help fill these gaps.
“I’ll be automatically signed up for everything.”
Only Part A and Part B can be automatic (and only if you’re receiving Social Security). Part D, Advantage, and Supplement plans always require active enrollment during specific windows.
“My spouse’s employer coverage protects me from penalties.”
Only if your spouse is actively working AND the employer has 20+ employees. Retiree coverage, COBRA, and marketplace plans do not qualify.
“I can sign up anytime.”
Medicare has specific enrollment periods. Missing your window can result in permanent penalties and delayed coverage. See all enrollment deadlines.
“I didn’t work enough to get Medicare.”
You may qualify through your spouse’s or ex-spouse’s work history. Even without enough quarters, you can purchase Part A. Eligibility through disability or ESRD doesn’t require work credits.

Not Sure What You Qualify For?

A quick review can clarify your eligibility, timeline, and next steps — at no cost.

Medicare Eligibility — Frequently Asked Questions

At what age am I eligible for Medicare?

Most people become eligible at age 65. However, you can qualify before 65 if you’ve received Social Security Disability benefits for 24 months, have been diagnosed with ALS (immediate eligibility), or have End-Stage Renal Disease requiring dialysis or transplant.

Do I have to be a U.S. citizen to get Medicare?

No. You can qualify as a legal permanent resident (green card holder) who has lived in the United States continuously for at least 5 years. You must also meet the age or disability requirements and have sufficient work history (or qualify through a spouse).

My spouse worked but I didn’t. Am I still eligible?

Yes. If your spouse has at least 40 quarters (10 years) of Medicare-tax-covered work, you can qualify for premium-free Part A based on their work history. This also applies to ex-spouses if the marriage lasted at least 10 years and you haven’t remarried.

I’m still working at 65. Do I have to sign up?

It depends on your employer size. If your employer has 20 or more employees, you can delay Part B without penalty. If your employer has fewer than 20 employees, Medicare becomes primary and you should enroll during your Initial Enrollment Period to avoid permanent penalties. Learn more about Part B enrollment.

Does COBRA count as employer coverage for delaying Medicare?

No. COBRA, retiree health plans, VA benefits, TRICARE, and marketplace plans do not qualify as current employer group health coverage. None of these allow you to delay Part B enrollment without facing permanent late enrollment penalties.

What if I never worked and my spouse never worked?

You can still enroll in Medicare at age 65, but you would need to pay a premium for Part A (up to $518/month in 2025). Part B is available to all eligible individuals regardless of work history, with the standard monthly premium.

Can I get Medicare if I’m under 65 with a disability?

Yes, but there is typically a 24-month waiting period after your first Social Security Disability (SSDI) payment. Medicare coverage begins automatically in month 25. The exception is ALS, which has no waiting period, and ESRD, which has a shorter waiting period.

What is a Medicare Supplement (Medigap) plan?

A Medicare Supplement plan works alongside Original Medicare to help cover deductibles, coinsurance, and gaps. It provides nationwide provider access but requires a separate Part D plan for prescriptions. See how it compares to Medicare Advantage.

Does my location affect my Medicare plan options?

Yes. Medicare Advantage plan availability, networks, premiums, and extra benefits vary significantly by where you live. Supplement plans are standardized nationally but premiums differ by location and carrier.

Questions About Your Medicare Eligibility?

Let’s review your situation, confirm your eligibility timeline, and find the right coverage for your needs.

Licensed independent Medicare advisor. Reviews provided at no cost to you.