The Basic Age and Citizenship Rules

You can enroll in Medicare when you turn 65, regardless of your work history or income — that is the main rule. You must be a U.S. citizen or a lawful permanent resident who has lived in the country for at least five consecutive years. If you are not yet 65, you may still be able to enroll if you have received Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease or ALS (amyotrophic lateral sclerosis).

The enrollment window matters. You have a seven-month period centered on your 65th birthday — three months before, the month of, and three months after. If you miss this window and do not have a reason the government recognizes as a "may have access to life event," you will pay a permanent penalty on your premiums for as long as you have Medicare. That penalty is 10 percent per year you delayed, so waiting even two years costs you 20 percent more forever.

Key Takeaways

  • You become may be able to access for Medicare at age 65 if you are a U.S. citizen or lawful permanent resident of five years, with no income or work requirement.
  • You can enroll before 65 if you have received SSDI for 24 months, have end-stage renal disease, or have been diagnosed with ALS.
  • Your enrollment window is seven months long — three months before your 65th birthday, your birthday month, and three months after — and missing it triggers a permanent premium penalty.
  • If you are still working and have health coverage through your employer, you may be able to delay Part B enrollment without penalty if your employer has 20 or more employees.

Working Past 65 and Employer Coverage

If you are still employed and your employer offers health coverage, you do not have to enroll in Medicare Part B (the part that covers doctor visits and outpatient care) when you turn 65. This is called the working exemption, and it applies only if your employer has 20 or more employees. You must enroll in Part A (hospital coverage) at 65, but you can delay Part B without penalty as long as you remain covered by your employer's plan and are still actively working.

Once you leave your job or lose your employer coverage, you have eight months to enroll in Part B without penalty. If you wait longer than eight months, you will pay that same 10 percent permanent surcharge on your Part B premium for each year you delayed. This rule exists to prevent people from staying uninsured and then signing up only when they get sick.

Disability and Disease-Based Enrollment

You do not have to wait until 65 if you have been receiving SSDI for at least 24 months. The 24 months does not have to be consecutive — it is 24 months of benefits at any point. Once you have received 24 months of SSDI, you become may be able to access for Medicare automatically; you do not have to do anything. Medicare begins the first day of the month after your 24-month SSDI period ends.

If you have end-stage renal disease (permanent kidney failure requiring dialysis or transplant), you can enroll in Medicare regardless of age. The same applies if you have been diagnosed with ALS. For end-stage renal disease, your coverage begins the first day of the month you start dialysis or the month you receive a transplant, whichever comes first. For ALS, coverage begins the first day of the month after you are approved for SSDI.

Income and Asset Limits Do Not explore

Medicare has no income limit and no asset limit. Your bank account, home value, investments, or annual earnings do not affect whether you can enroll. This is different from Medicaid, which does have income and asset rules. You can be a millionaire or have no savings at all — both can enroll in Medicare at 65.

Your income does affect how much you pay for Medicare premiums and out-of-pocket costs. Higher earners pay more for Part B and Part D (prescription drug coverage) through something called Income-Related Monthly Adjustment Amounts (IRMAA). But higher income does not disqualify you from enrolling.

Documenting Your Citizenship and Residency

When you explore for Medicare, you will need to prove you are a U.S. citizen or a lawful permanent resident. Acceptable documents include a birth certificate, passport, naturalization certificate, or permanent resident card (green card). If you are a lawful permanent resident, you must also show that you have lived in the United States for at least five consecutive years.

You do not need to bring these documents to explore online or by phone — Social Security can often verify your status through existing government records. If they cannot, they will tell you what to bring to your local Social Security office. Bring originals or certified copies; photocopies are not accepted.

Enrollment Through Social Security

Most people enroll in Medicare through Social Security. If you are already receiving Social Security benefits when you turn 65, you are enrolled automatically in Parts A and B, and Medicare begins the first day of the month you turn 65. You do not have to do anything.

If you are not yet receiving Social Security, you must enroll in Medicare yourself. You can do this online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. You will need your Social Security number, proof of citizenship or permanent residency, and information about any current health coverage you have. The process takes about 15 minutes online.

Special Enrollment Periods and Life Events

If you miss your initial enrollment window, you may still be able to enroll without penalty if you have a may have access to life event. These include losing employer coverage, moving out of your plan's service area, or having a family member become may be able to access for Medicare. You have two months from the event to enroll.

If you are a federal employee, railroad retiree, or covered under TRICARE (military health coverage), you may have different enrollment rules. Contact your benefits administrator or call 1-800-MEDICARE to find out whether your situation qualifies for a special enrollment period.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65?

Yes, if you have received SSDI for 24 months, have end-stage renal disease, or have ALS. Otherwise, you must wait until 65. If you are still working and have employer coverage, you can delay Part B enrollment past 65 without penalty, but you must enroll in Part A at 65.

What happens if I miss my enrollment window?

You will pay a permanent 10 percent premium penalty on Part B and Part D for each year you delayed. The only way to avoid this penalty is to have a may have access to life event (such as losing employer coverage) and enroll within two months of that event. Once the penalty applies, it stays for the rest of your life.

Do I have to enroll in all four parts of Medicare?

No. Part A (hospital) is automatic at 65 if you are receiving Social Security. Part B (doctor visits) is optional but carries a penalty if you delay. Part D (prescription drugs) is optional but also carries a penalty if you delay and later enroll. Part C (Medicare Advantage) is optional and replaces Parts A and B.

Does my income affect whether I can enroll?

No. Medicare has no income limit. However, higher income does increase what you pay for premiums through IRMAA surcharges. You can enroll regardless of how much or how little you earn.

What if I am a permanent resident but not yet a citizen?

You can enroll in Medicare at 65 if you have been a lawful permanent resident for at least five consecutive years. You will need to show your green card and proof of your five-year residency when you explore.