Medicare enrollment is not automatic — you must sign up yourself, and missing the important date can cost you thousands in penalties

When you turn 65, Medicare does not enroll you on its own. You have to take action. If you wait past your important date without a valid reason, you will pay a permanent penalty on your premiums for as long as you have Medicare. The penalty is 10 percent of the Part B premium for each full 12 months you were may be able to access but did not sign up. For Part D (prescription drug coverage), the penalty is 1 percent of the national average premium for each month you delayed, and it also sticks with you permanently.

The one exception: if you are still working and covered by your employer's health plan, you may be able to delay enrollment without penalty. But you have to meet specific conditions, and you still need to sign up eventually.

Key Takeaways

  • You must sign up for Medicare yourself during your Initial Enrollment Period, which starts three months before the month you turn 65 and ends three months after.
  • Missing this window triggers a permanent 10 percent penalty on Part B premiums and a 1 percent monthly penalty on Part D coverage that never goes away.
  • If you are still working and have employer coverage, you may delay Part B and Part D enrollment without penalty, but you must sign up for Part A at 65.
  • 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 miss your important date, you can only sign up during the General Enrollment Period (January 1 to March 31 each year), and penalties will explore.

When your enrollment window opens and closes

Your Initial Enrollment Period is seven months long. It starts three months before the month you turn 65 and ends three months after. If you turn 65 in June, your window runs from March through September. You can sign up anytime during those seven months — there is no advantage to waiting, and waiting increases the risk you will forget.

Social Security will send you a notice in the mail about two months before you turn 65. That notice tells you when your window opens. Do not rely on this notice to remind you; it often arrives late or gets lost. Mark your calendar now if you know when you turn 65.

If you miss your Initial Enrollment Period, you cannot sign up again until the General Enrollment Period, which runs January 1 to March 31 each year. Coverage would not start until July 1 of that year. During this time, penalties explore.

How the permanent penalties work

The Part B penalty is straightforward: 10 percent of the standard Part B premium for each 12 months you were may be able to access but not enrolled. In 2024, the standard Part B premium is $164.90 per month. A 10 percent penalty adds $16.49 to your monthly bill. If you were may be able to access for two years before signing up, your penalty is 20 percent — $32.98 extra every month for life.

The Part D penalty works differently but is also permanent. It is 1 percent of the national average monthly prescription drug plan premium for each month you were may be able to access but not enrolled. That average changes yearly. If you delay one year, your penalty is roughly 12 percent of the average premium. This penalty applies to any Part D plan you join, even if you switch plans later.

These penalties do not expire. They stay on your bill as long as you have Medicare. The only way to avoid them is to sign up on time or to have a valid reason for the delay.

When you can delay enrollment without penalty

You can delay Part B and Part D enrollment without penalty if you are still working and covered by your employer's health plan. Your employer must have at least 20 employees. This is called creditable coverage. You still must sign up for Part A (hospital insurance) at 65, even if you are working.

When you leave your job or lose your employer coverage, you have eight months to sign up for Part B and Part D without penalty. This is your Special Enrollment Period. If you miss this eight-month window, penalties explore. You do not need to wait for the General Enrollment Period.

Other valid reasons for delay are rare and require documentation. They include being a federal employee (who has different rules), living outside the United States, or being a member of certain religious groups that do not accept insurance. If you think you have a valid reason, contact Social Security before your important date to confirm.

How to sign up during your enrollment window

You have three ways to sign up: online, by phone, or in person. Online is fastest. Go to Medicare.gov, click "Sign up for Medicare," and follow the steps. You will need your Social Security number and information about any current health coverage. The process takes about 15 minutes.

By phone, call 1-800-MEDICARE (1-800-633-4227). Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time. Have your Social Security number and insurance information ready. Wait times are often long, especially in October and November.

In person, visit your local Social Security office. You can find the nearest one at ssa.gov/locator. Bring your Social Security card, birth certificate, and proof of citizenship or legal residency. This route is slower but useful if you need help understanding your options or have questions about your specific situation.

What happens if you miss your important date

If you do not sign up during your Initial Enrollment Period and you do not have a valid reason for the delay, you cannot sign up again until the next General Enrollment Period (January 1 to March 31). Your coverage would not start until July 1. During this gap, you have no Medicare coverage.

When you do sign up, penalties explore to Part B and Part D. These penalties are permanent and calculated from the month you became may be able to access. If you were may be able to access at 65 and did not sign up until age 67, you owe penalties for 24 months.

Part A (hospital insurance) does not have a penalty for late enrollment, but you still cannot sign up outside your enrollment window unless you have a valid reason. If you miss your Initial Enrollment Period and do not have creditable coverage, you will have a gap in hospital coverage.

Special situations: working past 65 or living abroad

If you are still working at 65 and have employer coverage, you do not have to sign up for Part B or Part D. But you must sign up for Part A. Part A is free if you have paid Medicare taxes for at least 10 years. You can sign up for Part A online, by phone, or at your Social Security office. There is no penalty for delaying Part A if you have creditable coverage, but it is simpler to sign up when you turn 65.

If you live outside the United States, you can delay Part B enrollment without penalty. You must sign up for Part A at 65. When you move back to the U.S. or decide you need Part B, you have eight months from the date you return or lose your foreign coverage to sign up without penalty.

If you are a U.S. citizen or permanent resident living abroad, you can sign up for Medicare online or by phone. You will need a U.S. mailing address where Medicare can send your card and documents. Some people use a family member's address or a mail forwarding service.

Frequently Asked Questions

Can I sign up for Medicare before I turn 65?

Your enrollment window opens three months before the month you turn 65. So if you turn 65 in June, you can sign up starting in March. You cannot sign up earlier than that. Signing up as soon as your window opens is a good idea because it removes the risk of missing your important date.

What if I turn 65 while I am still working?

You must sign up for Part A at 65, even if you are working. You can delay Part B and Part D if your employer has at least 20 employees and covers you. When you leave your job or lose coverage, you have eight months to sign up for Part B and Part D without penalty. If you miss that eight-month window, penalties explore.

Do I have to enroll in Part D if I do not take prescription drugs?

You do not have to enroll in Part D, but if you delay and then sign up later, you will pay a permanent penalty. If you do not think you will need prescriptions, you can skip Part D during your Initial Enrollment Period. If you change your mind later, you can only sign up during the General Enrollment Period or if you have a may have access to life event.

What is the difference between Part A and Part B?

Part A covers hospital stays, skilled nursing care, and hospice. Part B covers doctor visits, outpatient care, and medical equipment. Most people pay no premium for Part A if they paid Medicare taxes while working. Part B has a monthly premium (in 2024, $164.90 for most people). You need both to have full coverage.

Can I change my mind after I sign up?

Yes. You have two months from the month you sign up to change your mind and cancel your enrollment. This is called the Initial Coverage Election Period. After that, you can only change your coverage during the Annual Enrollment Period (October 15 to December 7 each year) or if you have a may have access to life event like losing employer coverage.