You must be 65 to enroll in Medicare, with rare exceptions for younger people with disabilities or end-stage renal disease

Medicare is a federal health insurance program, and the standard entry point is your 65th birthday. You do not have to wait until you turn 65 to sign up — you can enroll during the three months before your birthday month, the month you turn 65, and the three months after. If you miss that window, you will face a permanent penalty on your premiums unless you have a may have access to reason for the delay.

The age 65 rule applies whether you are still working or retired. Your employment status does not change the requirement. However, a small number of people younger than 65 can enroll: those who have been receiving Social Security Disability Insurance (SSDI) for 24 months, or those with end-stage renal disease or ALS (amyotrophic lateral sclerosis), regardless of age.

Key Takeaways

  • The standard age to enroll in Medicare is 65, and you can sign up starting three months before your birthday month.
  • If you miss your initial enrollment window, you will pay a higher premium for as long as you have Medicare unless you had a may have access to reason for the delay.
  • People under 65 who receive SSDI for 24 months, or who have end-stage renal disease or ALS, can enroll in Medicare before reaching 65.
  • You must be a U.S. citizen or permanent resident and have lived in the United States for at least five consecutive years to be covered.
  • Enrollment happens through Medicare.gov, by phone, or in person at a Social Security office — not through your employer or a private insurance company.

When your 65th birthday enrollment window opens and closes

Your Initial Enrollment Period (IEP) lasts seven months: three months before the month you turn 65, the month itself, and three months after. For example, if you turn 65 in June, you can enroll from March through September. Coverage typically begins the first day of the month you turn 65, though it can be delayed if you enroll late in your window.

The exact start date depends on when you sign up. If you enroll before the month you turn 65, coverage usually starts on the first day of the month you turn 65. If you enroll during the month you turn 65, coverage typically starts the first day of the following month. If you enroll after the month you turn 65, there is a further delay — coverage may not start until several months later.

This timing matters because any gap between when your current insurance ends and when Medicare begins leaves you uninsured. If you are still covered by an employer plan at 65, you have different rules: you can delay Medicare without penalty as long as you are actively employed and covered by that employer's plan, but you must enroll within eight months of losing that coverage.

The penalty for enrolling after your window closes

If you do not enroll during your Initial Enrollment Period and you do not have a may have access to reason for the delay, Medicare Part B (medical insurance) will cost you 10 percent more for each full year you were may be able to access but not enrolled. This penalty is permanent — it stays with you for life, even if you enroll years later.

The same penalty applies to Medicare Part D (prescription drug coverage). If you go 63 days or longer without creditable drug coverage — meaning coverage as good as Medicare's — you will pay 1 percent more per month for every month you were without it. That penalty also lasts for life.

A few situations waive these penalties. If you were covered by an employer plan or a spouse's employer plan when you turned 65, you can delay without penalty. If you receive a notice from Medicare saying you were not required to enroll, that counts as a may have access to reason. If you are a federal employee, your coverage may also protect you from penalties. The key is having documentation of the reason — Medicare will ask for proof.

Who can enroll before age 65

People who receive Social Security Disability Insurance (SSDI) become may be able to access for Medicare after 24 months of receiving benefits, regardless of age. You do not have to do anything — Medicare will contact you automatically about two months before your 24-month mark and enroll you unless you decline.

People with end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or a transplant — can enroll in Medicare at any age. You have a three-month enrollment window: the month your kidney failure begins, plus three months after. If you receive a transplant, your Medicare coverage continues for 36 months after the transplant, even if the transplant fails.

People with ALS (Lou Gehrig's disease) can enroll when ready upon diagnosis, without waiting for any benefit period. You can sign up as soon as you receive your diagnosis and have documentation from your doctor.

Citizenship and residency requirements

You must be a U.S. citizen or permanent resident to enroll in Medicare. Permanent residents are people with a green card. If you are a citizen, you meet this requirement automatically. If you are a permanent resident, you will need to provide proof — your green card or a document showing your status.

You must also have lived in the United States for at least five consecutive years when ready before you enroll. This means five years without leaving the country for more than 30 days at a time. If you have left the country for longer stretches, the five-year clock restarts. Temporary absences for medical treatment or family emergencies may not break the clock, but you should verify your specific situation with Medicare before enrolling.

How to enroll when you reach 65

You can enroll through three routes: Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. Online enrollment is the fastest — you can complete it in 10 to 15 minutes if you have your Social Security number and information about your current health coverage.

By phone, a representative will walk you through the same questions and can answer questions about your specific situation. Wait times vary, but calling early in the week and early in the day usually means shorter holds. In person, a Social Security representative can help you enroll and answer questions about your local options.

You will need your Social Security number, proof of citizenship or permanent residency, and information about any current health coverage you have. If you are still working and covered by an employer plan, bring documentation of that coverage — it may affect your enrollment date or protect you from penalties.

What happens after you turn 65 if you do not enroll

If you reach 65 and do not enroll in Medicare, you remain on whatever coverage you have — an employer plan, a spouse's plan, or private insurance. You are not automatically enrolled, and there is no grace period. The penalties for late enrollment begin accruing when ready after your Initial Enrollment Period ends.

If you are uninsured at 65 and do not enroll, you have no federal health coverage. You can enroll later, but you will owe the permanent penalty on Part B and Part D premiums. The only way to avoid the penalty is to show Medicare that you had a may have access to reason for the delay — usually proof of employer coverage or a notice from Medicare saying you were not required to enroll.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65 if I am still working?

No, unless you have SSDI, end-stage renal disease, or ALS. If you are still working and covered by your employer's health plan, you can delay Medicare without penalty as long as you enroll within eight months of leaving that job or losing the coverage. You do not have to wait until 65 to enroll — you can enroll as soon as you lose the employer coverage.

What if I turn 65 while I am out of the country?

You can still enroll during your Initial Enrollment Period, even if you are abroad. You can enroll online at Medicare.gov or by phone. However, Medicare Part A (hospital insurance) and Part B (medical insurance) do not cover care outside the United States, so coverage while you are traveling is limited. You should enroll before you leave or as soon as you return.

Do I have to enroll in all parts of Medicare at 65?

No. Part A (hospital insurance) is usually free if you or your spouse paid Medicare taxes while working, and most people enroll in it. Part B (medical insurance) has a monthly premium and is optional. Part D (prescription drug coverage) is optional. However, if you delay Part B or Part D without a may have access to reason, you will face permanent penalties when you do enroll.

What if I miss my enrollment window by a few months?

You can still enroll, but you will owe the permanent late-enrollment penalty on Part B and Part D unless you have a may have access to reason for the delay. The penalty is 10 percent per year for Part B and 1 percent per month for Part D. You should enroll as soon as you realize you missed the window and gather any documentation of a may have access to reason to submit with your process.

Does my age change if I have a birthday during the enrollment process?

No. Your age for Medicare purposes is determined by your birth date, not by when you complete the enrollment. If you are born on June 15 and you enroll in March, you are still considered to be turning 65 in June, and your coverage will reflect that date.