When Does Medicare Start?

For most people, Medicare starts at age 65. If you're living with a disability or with certain conditions, Medicare can start sooner. If you’re working past 65, you may be able to delay Medicare.

There are penalties for missing enrollment dates, so it’s important to understand the timeline.

Medicare usually starts when you’re 65, depending on your Medicare eligibility. But it doesn’t necessarily start on your birthday. Medicare coverage always kicks in on the first day of the month.

Your Medicare coverage start date depends on when you sign up^[0]

Do you automatically get Medicare when you turn 65?

If you’ve applied for Social Security benefits or Railroad Retirement Board benefits, you’ll automatically get Medicare Part A when you become eligible for Medicare. If you’ve been getting benefits for at least four months, you’ll get Part A and Part B when you turn 65. You can choose whether to keep Part B^[0]

If you haven't applied for Social Security, you’ll have to sign up for Medicare yourself. You should enroll in the three months before your birthday to avoid any coverage gap.

» MORE: Medicare and Social Security

If you’re under 65, you can qualify for Medicare based on disability or specific health conditions. Here’s when your Medicare coverage starts:

• Social Security Disability Insurance (SSDI) recipients: People who get disability benefits from Social Security automatically receive Medicare coverage after 24 months^[0]

  Social Security Administration. Medicare information. Accessed Mar 2, 2026.

  View all sources

  .

• People who have ALS (Lou Gehrig’s disease): You automatically receive Medicare coverage the same month that disability benefits start.

• People who have end-stage renal disease (ESRD): You can usually apply for Medicare starting on the first day of the fourth month of dialysis treatments^[0]

  Centers for Medicare & Medicaid Services. End-State Renal Disease (ESRD). Accessed Mar 2, 2026.

  View all sources

  . If you’re getting a kidney transplant, Medicare coverage can start the month you’re admitted to a hospital for the transplant, if the transplant happens that month or within the next two months. Transplant delays may move Medicare’s starting date out, too. Get more information on ESRD and Medicare on Medicare.gov.

» MORE: Medicare for people with disabilities

Most people start Medicare during their initial enrollment period, but your window may be different depending on your work status and whether you’ve missed previous deadlines.

Medicare initial enrollment period (IEP): Turning 65

This is the seven-month window that includes the three months before your birthday month, your 65th birthday month and the three months after. If you were born on June 17, your enrollment window would be March 1 through Sept. 30. Aim to sign up before June, and your coverage will start June 1.

If your birthday is on the first of the month, your enrollment period shifts back one month. If you were born on June 1, your enrollment window would be Feb. 1 through Aug. 30. Aim to sign up before May, and your coverage will start May 1.

» MORE: How do I sign up for Medicare?

Medicare general enrollment period (GEP): If you missed your window

If you miss your initial enrollment period, you can sign up for premium-free Medicare Part A any time. But you must wait until Medicare’s general enrollment period, Jan. 1 to March 31, to sign up for the other parts of Medicare. Coverage starts the month after you sign up. Those who miss the initial enrollment period for Medicare Part B and Part D usually have to pay permanently higher premiums due to penalties^[0]

You may be able to enroll outside of this window — and potentially avoid penalties — if you qualify for a special enrollment period.

Medicare special enrollment period (SEP): Working past 65 and other special circumstances

You can qualify for a special enrollment period and avoid penalties if you’re working past 65 and have creditable coverage through your employer^[0]

You then have two months to enroll in Medicare Advantage or Part D, and eight months to enroll in Medicare Part B. (Though if you enroll in a Medicare Advantage plan, you’ll have to enroll in Part B at that time.) If you apply using a special enrollment period and your application is approved, your coverage starts the first day of the following month.

» MORE: When to sign up for Medicare if you’re still working past 65

Other things that might qualify you for a SEP include missing a chance to sign up because you were affected by a natural disaster or missing a chance to enroll because a health plan or employer gave you incorrect information. To apply for a SEP, fill out the Application for Medicare Part A and Part B Special Enrollment Period and fax or mail to your local Social Security office.

» MORE: Original Medicare vs. Medicare Advantage: How to choose

If you don’t sign up for Medicare when you first become eligible, you could end up facing permanent late enrollment penalties, unless you’re still working and have creditable coverage from your employer.

Here are the Medicare late enrollment penalties:

If you’re unsure when you can sign up for Medicare, check your specific situation with Medicare directly.