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

Medicare may be able to access begins the month you turn 65, regardless of whether you have retired or are still working. You do not have to stop working to enroll. The enrollment window opens three months before your 65th birthday and closes three months after it — a seven-month window in total. If you miss this window, you may face a permanent penalty on your premiums, so the timing matters.

There are two smaller groups who can enroll before 65. People who have received Social Security Disability Insurance (SSDI) for 24 months become may be able to access at any age. People with end-stage renal disease (ESRD) — permanent kidney failure requiring dialysis or transplant — can enroll when ready upon diagnosis, also at any age. These are the only paths to Medicare before 65.

Key Takeaways

  • You become may be able to access for Medicare the month you turn 65, and you have a seven-month enrollment window centered on that birthday.
  • If you delay enrolling past your initial window without a valid reason, you will pay a permanent 10 percent penalty on Part B premiums for as long as you have Medicare.
  • You can enroll before 65 only if you have been on SSDI for 24 months or have end-stage renal disease requiring dialysis or transplant.
  • Enrollment happens through Social Security, Medicare.gov, or by phone at 1-800-MEDICARE, not through your doctor or health plan.

What happens when you turn 65

The month you turn 65, you become may be able to access for Medicare Part A (hospital insurance) and Part B (medical insurance). You do not have to do anything if you are already receiving Social Security benefits — Medicare will enroll you automatically about three months before your 65th birthday. You will receive your Medicare card in the mail.

If you are not yet receiving Social Security, you must enroll yourself. You can do this online at Medicare.gov, by calling 1-800-MEDICARE, or by visiting your local Social Security office in person. The enrollment window runs from three months before your birthday through three months after. Enrolling early — as soon as the window opens — prevents mistakes and gives you time to resolve any problems before coverage starts.

Why the enrollment window matters

Your initial enrollment period is a one-time window. If you miss it, you enter what Medicare calls the "general enrollment period," which runs January 1 through March 31 each year. Coverage under general enrollment does not start until July 1 of that year, creating a gap. More importantly, you will owe a permanent penalty.

The Part B late enrollment penalty is 10 percent of the standard premium for each full year you delayed. If you were supposed to enroll at 65 and did not enroll until age 68, you owe a 30 percent penalty for life. The same applies to Part D (prescription drug coverage) — a 1 percent penalty per month of delay, also permanent. These penalties do not expire.

There is one exception: if you had creditable health coverage (through an employer or union) while you were 65 or older, you can enroll without penalty during an eight-month window after that coverage ends. You will need to prove you had that coverage, so keep your plan documents.

Enrolling before 65 if you have a disability

If you receive SSDI, you become may be able to access for Medicare after you have been on disability for 24 months. The 24-month clock starts the month your disability benefits begin, not the month you applied. You will be enrolled automatically — you do not need to do anything. Your Medicare card arrives in the mail about a month before coverage starts.

If you are on SSDI and approaching your 24-month mark, check your Social Security account online or call 1-800-772-1213 to confirm the exact date. Some people are surprised to learn they are already may be able to access. If you have questions about your specific situation, Social Security can walk you through it.

Enrolling before 65 if you have end-stage renal disease

End-stage renal disease means your kidneys no longer work and you need dialysis or a transplant to survive. You become may be able to access for Medicare the month your dialysis or transplant treatment begins. You do not have to be 65, and you do not have to have worked a certain number of years — ESRD is the only diagnosis that overrides the age and work history requirements.

Your dialysis center or transplant team will help you enroll. They often have a social worker or patient advocate who handles Medicare paperwork. If you are unsure whether your condition qualifies, ask your nephrologist (kidney doctor) or call Medicare at 1-800-MEDICARE with your medical records available.

What you need to know about work and Medicare

You can work and have Medicare at the same time. Turning 65 does not require you to retire. If you are still working and your employer offers health insurance, you may want to delay enrolling in Medicare Part B and instead stay on your employer plan. This is allowed if your employer has 20 or more employees.

If you delay Part B while covered by an employer plan, you will not face a late enrollment penalty when you do enroll, as long as you enroll within eight months of losing that coverage. You will need to provide proof that you had employer coverage. Keep your plan documents for this reason.

How to enroll and what documents you need

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

Have these documents ready: your Social Security number, your birth certificate or passport, proof of citizenship (passport, naturalization papers, or birth certificate), and information about any current health insurance. If you are enrolling through Social Security because you are not yet receiving benefits, you will also need proof of income or a tax return from the past two years.

Frequently Asked Questions

What if I turn 65 while still working full-time?

You can enroll in Medicare while working. If your employer has 20 or more employees and offers health insurance, you may delay Part B without penalty. Enroll in Part A (hospital insurance) anyway — it is free if you or your spouse paid Medicare taxes for 10 years, and it covers hospital stays even while you are working.

Can I enroll in Medicare before I turn 65 if I am not disabled?

No. The only paths to Medicare before 65 are SSDI (after 24 months) or end-stage renal disease. If you are unemployed or uninsured before 65, you will need to find coverage through the Affordable Care Act marketplace, COBRA, or a spouse's plan until you reach 65.

What happens if I miss my enrollment window?

You can still enroll during the general enrollment period (January 1 through March 31), but coverage does not start until July 1, leaving you uninsured for months. You will also owe a permanent 10 percent penalty on Part B premiums. The only way to avoid the penalty is to prove you had creditable coverage through an employer during the time you were supposed to enroll.

Do I have to enroll in Part B when I turn 65?

Part A (hospital insurance) is automatic if you are receiving Social Security. Part B (medical insurance) is optional, but if you delay without creditable coverage, you will owe a permanent penalty. Most people should enroll in Part B at 65, but discuss your specific situation with a Social Security representative or Medicare counselor.

How do I prove I had employer coverage to avoid a late penalty?

Keep your health plan documents — the summary of benefits, your ID card, or a letter from your employer confirming coverage dates. When you enroll late, tell Medicare you had employer coverage and provide these documents. Medicare will review them to determine whether the penalty applies.