The Basic Rule: Age 65 and Older, Plus Some Younger People

You become covered by Medicare automatically when you turn 65, as long as you or your spouse paid Medicare taxes while working. You do not have to do anything on your birthday — the coverage starts whether you ask for it or not. If you were born on the first of the month, coverage begins the month before. If you were born on any other day, it begins the month you turn 65.

Medicare also covers some people under 65. You may be covered if you have been receiving Social Security disability benefits for 24 months, if you have end-stage renal disease (permanent kidney failure requiring dialysis or transplant), or if you have been diagnosed with amyotrophic lateral sclerosis (ALS). These three groups do not have to wait until 65.

If you are not yet 65 and do not fall into one of those three categories, you are not covered by Medicare, even if you are retired or not working. You would need to find coverage through your former employer, the Affordable Care Act marketplace, Medicaid, or another source.

Key Takeaways

  • You are automatically enrolled in Medicare when you turn 65 if you or your spouse paid Medicare taxes for at least 10 years while working.
  • People under 65 who receive Social Security disability benefits for 24 months, have end-stage renal disease, or have ALS are also covered by Medicare.
  • If you are not a U.S. citizen, you must have been a permanent resident for at least five years to be covered at 65.
  • Delaying enrollment after 65 can result in permanent penalties on your premiums, so understanding your enrollment window matters even if you plan to delay coverage.

Work History and Citizenship Requirements

Medicare coverage at 65 depends on your work history or your spouse's work history. You need at least 40 quarters of Medicare tax contributions — roughly 10 years of work — to be covered. These quarters do not have to be consecutive, and they do not have to be recent. If you worked 10 years at any point in your life and paid Medicare taxes, you meet this requirement.

If you did not work 10 years yourself, you may still be covered based on your spouse's work history. If your spouse is 62 or older, you can be covered on their record even if you never worked. If your spouse is younger than 62, you can be covered on their record only if you are caring for their child who is under 16.

If you are not a U.S. citizen, you must have been a permanent resident for at least five consecutive years when ready before turning 65 to be covered. Temporary visas, work permits, and other non-permanent status do not count toward this requirement.

When Coverage Starts and Enrollment Periods

Your coverage begins the first day of the month you turn 65, or the first day of the month before if your birthday is the first of the month. You do not need to sign up — it happens automatically if you are already receiving Social Security benefits.

If you are not yet receiving Social Security when you turn 65, you should still sign up for Medicare during your initial enrollment period. This period runs from three months before you turn 65 through three months after. If you miss this window and do not have other may have access to coverage (such as an active employer health plan), you will pay a permanent 10 percent penalty on your Part B premium for as long as you have Medicare.

If you are still working and covered by your employer's health plan at 65, you can delay Medicare enrollment without penalty as long as your employer has 20 or more employees. Once you leave that job or lose that coverage, you have eight months to sign up for Medicare without penalty.

People Under 65 Covered by Medicare

If you are receiving Social Security Disability Insurance (SSDI) benefits, you become covered by Medicare after you have been on disability for 24 months. The 24 months are counted from the date your disability began, not from the date you first received a check. Once you reach 65, your disability coverage automatically converts to regular Medicare Part A and Part B.

If you have end-stage renal disease, you are covered by Medicare regardless of age. Coverage begins the first day of the month you start dialysis, or the first day of the month you have a kidney transplant. If you have a transplant, coverage continues for 36 months after the transplant, even if the transplant fails and you go back on dialysis.

If you have been diagnosed with ALS, you are covered by Medicare when ready. You do not have to wait for disability approval or meet any other condition. Coverage begins the first day of the month you are diagnosed.

What Happens If You Do Not Meet the Requirements

If you turn 65 but do not have 40 quarters of Medicare tax contributions and cannot claim coverage through a spouse, you are not automatically covered by Medicare. You can still buy into Medicare Part A by paying a monthly premium, but this option is only available if you are 65 or older and a U.S. citizen or permanent resident.

The cost of buying in varies depending on how many quarters of coverage you have. If you have 30 to 39 quarters, you pay a reduced premium. If you have fewer than 30 quarters, you pay the full premium. These premiums change each year.

If you cannot afford to buy into Medicare Part A, you may be covered by Medicaid instead, depending on your income and your state's rules. Some states cover more people than others. You can contact your state Medicaid office or call 211 to find out what coverage options exist in your area.

Enrollment and Documentation You Will Need

If you are already receiving Social Security benefits when you turn 65, Medicare enrollment happens automatically and you do not need to do anything. Social Security will send you a Medicare card in the mail about two weeks before your coverage starts.

If you are not receiving Social Security, you need to sign up for Medicare yourself during your initial enrollment period. 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 and proof of citizenship or permanent residency.

If you are under 65 and covered because of disability or end-stage renal disease, Social Security will contact you about Medicare enrollment. If you have ALS, you will need to contact Social Security yourself to enroll, as the process is not automatic.

Special Situations: Government Employees and Non-Work Visas

If you worked for the federal government, some state governments, or some local governments, you may not have paid Medicare taxes. In this case, you do not have 40 quarters of coverage and cannot be automatically enrolled at 65. You can still buy into Medicare Part A if you are 65 or older, but you will pay the full premium.

If you came to the United States on a work visa and paid Medicare taxes during that time, those quarters count toward your 40-quarter requirement. If you came on a non-work visa (such as a student visa) and did not pay Medicare taxes, those years do not count. Only years in which you actually paid Medicare tax count.

If you are a permanent resident who has not yet been a resident for five consecutive years, you cannot be covered by Medicare at 65. You will need to wait until you have completed five years of permanent residency, or find other coverage in the meantime.

Frequently Asked Questions

What if I am 65 but still working and do not want Medicare yet?

If your employer has 20 or more employees and covers you under their health plan, you can delay Medicare without penalty. Once you leave that job or lose that coverage, you have eight months to sign up without penalty. If your employer has fewer than 20 employees, you should sign up for Medicare when you turn 65 to avoid penalties.

Can I get Medicare if I am not a U.S. citizen?

Yes, if you are a permanent resident and have been a permanent resident for at least five consecutive years. Temporary visas, work permits, and other non-permanent status do not count. You must meet the five-year requirement before you turn 65 to be covered automatically.

Do I lose Medicare if I move out of the United States?

Medicare Part A (hospital coverage) works in any country. Medicare Part B (doctor visits) and Part D (prescription drugs) generally do not cover care outside the U.S., except in limited situations near the border or on a cruise ship. If you move abroad permanently, you should contact Social Security to understand how your coverage changes.

What if I worked in another country — does that count toward the 40 quarters?

Work in another country does not count toward your 40 quarters unless you paid U.S. Medicare taxes on that income. If you worked for a U.S. employer or a U.S. citizen abroad and paid Medicare taxes, those quarters count. If you worked for a foreign employer, they do not count.

Can my adult child be covered under my Medicare?

No. Medicare does not cover dependents the way employer health plans do. Your adult children must have their own coverage through their employer, the Affordable Care Act marketplace, Medicaid, or another source.