You have to sign up for Medicare; it does not start on its own

No. Turning 65 does not automatically enroll you in Medicare. You must take action to sign up, and the timing matters — if you miss the important date, you may pay a penalty for as long as you have Medicare.

The government does not know your birthday or track when you turn 65. Medicare enrollment is your responsibility. Most people have a window of time around their 65th birthday to sign up without penalty, but that window closes, and the rules differ depending on whether you are still working and what kind of coverage you already have.

Key Takeaways

  • You must sign up for Medicare yourself during your Initial Enrollment Period, which runs three months before your 65th birthday through three months after.
  • If you are still working and covered by your employer's health plan, you may be able to delay Part B enrollment without penalty, but you must tell Medicare this in writing.
  • Missing your enrollment window can result in a permanent 10% monthly penalty on Part B premiums and a 1% monthly penalty on Part D (prescription drug coverage).
  • You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
  • If you are already receiving Social Security benefits, you will be enrolled in Part A and Part B automatically, but you still need to choose a Part D plan if you want prescription drug coverage.

Your Initial Enrollment Period: the three-month window before and after 65

Your Initial Enrollment Period is seven months long: it starts three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your enrollment period runs from March through September.

During this window, you can sign up for Medicare Part A (hospital insurance) and Part B (medical insurance) without waiting periods or penalties. This is your main chance to enroll without cost. If you sign up before your birthday month, coverage begins the month you turn 65. If you sign up during your birthday month or after, there may be a one-month delay in your coverage start date.

After this seven-month window closes, you enter what Medicare calls the General Enrollment Period, which runs January 1 through March 31 each year. You can still sign up then, but penalties explore, and your coverage does not start until July 1 of that year.

The exception: if you are still working and have employer coverage

If you are still employed and your employer offers health insurance, you may be able to delay Part B enrollment without penalty. This is called creditable coverage. Your employer plan must be based on current employment (not retiree coverage), and your employer must have at least 20 employees.

To use this exception, you must tell Medicare in writing that you are delaying Part B because of active employment. You cannot straightforward assume you are covered — you need to notify Medicare directly. You can do this when you sign up for Part A, or you can contact Social Security to report your employment status.

Once you leave your job or lose your employer coverage, you have eight months to sign up for Part B without penalty. If you miss that window, the 10% monthly penalty applies for as long as you have Medicare.

What happens if you miss your enrollment important date

Missing your Initial Enrollment Period triggers a late enrollment penalty on Part B. The penalty is 10% of the standard Part B premium for each full 12 months you were may be able to access but not enrolled. That percentage is added to your premium permanently — it does not go away after a few years.

Part D (prescription drug coverage) has a separate penalty: 1% of the national average Part D premium for each month you were without coverage. Like the Part B penalty, this also stays with you for life.

The only way to avoid these penalties is to have had creditable coverage (employer insurance or other may have access to coverage) during the time you were not enrolled in Medicare. If you did, keep records of that coverage — you may need to show proof to Medicare.

How to sign up: three ways to enroll

You can sign up for Medicare in three ways. The fastest is online at Medicare.gov — you can create an account, review your options, and submit your enrollment there. You will need your Social Security number and information about any current health coverage.

You can also call 1-800-MEDICARE (1-800-633-4227) to speak with someone who can walk you through the process. The line is open 24 hours a day, seven days a week. Have your Social Security number and any employer or insurance information ready.

A third option is to visit your local Social Security office in person. You can find the nearest office at ssa.gov or by calling 1-800-772-1213. Bring your Social Security card, proof of citizenship or legal residency, and proof of age.

If you are already receiving Social Security: you may be auto-enrolled

If you are already collecting Social Security retirement or disability benefits when you turn 65, you will be automatically enrolled in Medicare Part A and Part B. You do not need to do anything for these two parts.

However, you still need to choose a Part D plan (prescription drug coverage) if you want it. Part D is not automatic. You can sign up for Part D during your Initial Enrollment Period using the same methods listed above, or during the annual open enrollment period (October 15 through December 7 each year).

Even if you do not take any prescription drugs now, consider signing up for Part D during your Initial Enrollment Period. If you wait and later decide you need it, you will face the 1% monthly penalty for each month you were without coverage.

What to have ready before you sign up

Gather these documents before you enroll: your Social Security number, your birth date, your citizenship or legal residency status, and information about any current health insurance (employer plan, retiree coverage, or individual policy). If you are signing up online or by mail, you will also need an email address.

If you have had a gap in health coverage or are unsure whether your employer plan counts as creditable coverage, write down the dates you had that coverage and the name of the plan. You may need this information to explain any delay in your Medicare enrollment.

Keep copies of any enrollment confirmation you receive. Medicare will send you a confirmation letter or email, and you should save this for your records.

Frequently Asked Questions

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

You still need to sign up for Medicare during your Initial Enrollment Period, even if you are working. If your employer offers health insurance and you are covered by it, you can delay Part B without penalty — but you must notify Medicare in writing that you are delaying due to active employment. Part A (hospital insurance) is usually recommended even while working, since it has no monthly premium if you or your spouse paid Medicare taxes for at least 10 years.

Can I change my mind after I sign up?

Yes, but only during certain times. You have a seven-day window after you first enroll to cancel and start over. After that, you can make changes during the annual open enrollment period (October 15 through December 7) or if you have a may have access to life event, such as losing employer coverage or moving to a different state. Some changes take effect when ready; others begin January 1.

What if I do not want Medicare Part B right now?

You can sign up for Part A only and delay Part B, as long as you notify Medicare that you are delaying due to active employment and creditable coverage. If you do not have creditable coverage and you decline Part B, you will face a late enrollment penalty when you eventually sign up. The exception is if you are not yet receiving Social Security — in that case, you can delay both Part A and Part B without penalty until you claim benefits or turn 70.

Do I need to do anything if I am already on Social Security?

You will be automatically enrolled in Part A and Part B, so no action is needed for those. However, you should still review your Part D options and sign up for a prescription drug plan during your Initial Enrollment Period if you want coverage. Even if you do not take medications now, enrolling during this window avoids future penalties.

What if I miss my enrollment important date by just a few weeks?

Penalties begin the month after your Initial Enrollment Period ends. There is no grace period. If you realize you missed the important date, contact Medicare when ready — you may be able to enroll during the next General Enrollment Period (January 1 through March 31), but your coverage will not start until July 1, and penalties will explore. It is worth calling 1-800-MEDICARE to discuss your specific situation.