When and how to register for Medicare

You can register for Medicare starting three months before the month you turn 65. Most people register through Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. The important date to register without a penalty is the end of the month you turn 65, though you can register after that date if you need to.

If you are already receiving Social Security benefits, Medicare will contact you automatically about three months before your 65th birthday. You do not have to do anything — your coverage will start automatically on the first day of the month you turn 65. If you are not yet receiving Social Security, you will need to register yourself.

The registration process itself takes about 10 minutes online or 15 minutes on the phone. You will need your Social Security number, proof of citizenship or legal residency, and information about any current health insurance you have. Have these documents ready before you start.

Key Takeaways

  • You can register three months before you turn 65, and you must register by the end of the month you turn 65 to avoid a permanent penalty on your premiums.
  • If you already receive Social Security, Medicare will enroll you automatically — you do not need to do anything.
  • If you do not receive Social Security, you must register yourself through Medicare.gov, by phone, or at a Social Security office.
  • You will need your Social Security number, proof of citizenship or legal residency, and details about any current health insurance.
  • Part A (hospital insurance) is usually free if you or your spouse paid Medicare taxes for at least 10 years, but you still must register to set up it.

What happens if you miss the registration important date

If you do not register by the end of the month you turn 65, you will pay a permanent penalty on your Part B premiums (doctor and outpatient care). The penalty is 10 percent of the standard Part B premium for each full 12 months you were not registered. That penalty stays with you for the rest of your life, even if you register later.

There is one exception: if you were still covered by a health plan through your job or your spouse's job when you turned 65, you may not owe a penalty. You have eight months after that coverage ends to register without penalty. This is called a Special Enrollment Period. You will need to show proof that you had group health coverage — usually a letter from your employer or health plan stating the coverage dates.

If you think you may have access to for a Special Enrollment Period, register as soon as your group coverage ends. Bring the proof with you. If you register after the important date without this proof, you will owe the penalty.

Choosing between Part A, Part B, and Part D

Medicare has different parts, and you need to understand what each covers before you register. Part A covers hospital stays, skilled nursing care, and hospice. Part B covers doctor visits, outpatient care, and medical equipment. Part D covers prescription drugs. When you register, you will choose which parts you want.

Most people get Part A automatically if they or their spouse paid Medicare taxes for at least 10 years. Part A has no monthly premium for most people, but you still must register to set up it. Part B has a monthly premium that changes each year — in 2024 it was $164.90 for most people, but higher earners pay more. Part D also has a monthly premium that varies by plan.

If you delay Part B or Part D registration and do not have a may have access to reason (like group health coverage through work), you will owe a permanent penalty. The Part B penalty is 10 percent per year, and the Part D penalty is 1 percent per month. Register on time to avoid these costs.

Original Medicare versus Medicare Advantage

When you register, you will choose between Original Medicare (Part A and Part B) or a Medicare Advantage plan (Part C). You cannot have both at the same time. This is an important choice because it affects which doctors you can see, what you pay, and whether you need separate drug coverage.

Original Medicare lets you see any doctor or hospital that accepts Medicare. You pay a deductible and coinsurance for each service. You will need to buy a separate Part D plan for prescription drugs, and you may want to buy a Medigap policy (supplemental insurance) to cover costs that Medicare does not pay.

Medicare Advantage plans are run by private insurance companies. They usually have lower monthly premiums than Original Medicare plus Medigap, but they limit which doctors you can see and often require referrals. Most Medicare Advantage plans include prescription drug coverage, so you do not buy Part D separately. You will pay out-of-pocket costs when you see a doctor, and these vary by plan.

You do not have to decide right away. You have until December 7 each year to change your choice during the Annual Enrollment Period. If you register in the month you turn 65, you can change your mind during that first enrollment period without penalty.

Documents you will need to register

Have these documents ready before you start the registration process:

  • Your Social Security number
  • Proof of citizenship or legal residency (passport, birth certificate, naturalization papers, or permanent resident card)
  • Information about any current health insurance (policy number, employer name, or plan name)
  • If you are registering by mail, a completed CMS-40B form (available on Medicare.gov)

If you are registering online or by phone, you will not need to mail documents unless Medicare asks for them later. If you are registering in person at a Social Security office, bring originals or certified copies of your proof of citizenship or residency.

If you are claiming a Special Enrollment Period because you had group health coverage, bring a letter from your employer or health plan showing the dates your coverage was active. This letter must show when your coverage ended, not just when you were employed.

Where to register and what to expect

Online at Medicare.gov: Go to the "Register for Medicare" section. You will answer questions about your age, citizenship, and current coverage. The process takes about 10 minutes. You will get a confirmation number at the end. Medicare will mail you a Medicare card within two weeks.

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 documents ready. The call takes about 15 minutes. You will receive a confirmation number and your Medicare card will arrive by mail within two weeks.

In person: Visit your local Social Security office. You can find the nearest office on Social Security.gov. Bring your documents and proof of citizenship or residency. Processing takes about 30 minutes. You will get a receipt, and your Medicare card will arrive by mail within two weeks.

Your Medicare coverage starts on the first day of the month you turn 65, even if your card has not arrived yet. You can use your confirmation number to show you are covered. If your card does not arrive within three weeks, call 1-800-MEDICARE to request a replacement.

What to do after you register

After you register, Medicare will send you a welcome package with your Medicare card, a handbook called "Medicare & You," and information about enrollment important date. Read the handbook — it explains what each part covers and what you will pay.

If you chose Original Medicare, you have until December 7 of the year you turn 65 to buy a Medigap policy or a Part D drug plan. If you wait until after December 7, you may pay higher premiums or lose coverage for that year. If you chose Medicare Advantage, your plan will start on the first day of the month you turn 65.

Mark your calendar for December 7 each year. That is the last day of the Annual Enrollment Period, when you can change your Medicare coverage for the following year. If you do not make changes, your current coverage continues automatically.

Frequently Asked Questions

Do I have to register if I am still working and have health insurance through my job?

No, you do not have to register at 65 if you have group health coverage through your current job or your spouse's current job. You can delay Part B registration without penalty. However, you should still register for Part A (hospital insurance) because it is usually free and covers hospital stays even while you are working. When your job coverage ends, you have eight months to register for Part B without penalty.

What if I am not a U.S. citizen?

You can register for Medicare if you are a lawful permanent resident (green card holder) and have lived in the United States for at least five years. You will need to show your permanent resident card or other proof of legal residency. If you are not a permanent resident, you may not be able to register, but contact Medicare to discuss your situation.

Can I register before I turn 65?

Yes, you can register starting three months before the month you turn 65. For example, if you turn 65 in June, you can register starting in March. Registering early gives you time to choose a plan and receive your Medicare card before your coverage starts. You do not have to wait until the month you turn 65.

What if I already have Medicare because I am disabled or have end-stage renal disease?

If you are already on Medicare before age 65, you do not need to register again when you turn 65. Your coverage will continue automatically. Your Medicare card will not change. If you need to make changes to your coverage, you can do so during the Annual Enrollment Period.

How much will Medicare cost me each month?

Part A is usually free if you or your spouse paid Medicare taxes for at least 10 years. Part B costs vary by year and income — in 2024 most people paid $164.90 per month, but higher earners paid more. Part D (prescription drugs) costs vary by plan, usually between $5 and $100 per month. If you choose Medicare Advantage, the monthly premium varies by plan and location. You will see the exact costs when you register.