When and how to sign up for Medicare

You can sign up for Medicare starting three months before you turn 65, during your birthday month, and for three months after. This seven-month window is called your Initial Enrollment Period. You sign up through Medicare directly — either online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

If you do not sign up during this window, you can still sign up later, but you may face a permanent penalty on your premiums. The penalty is 10 percent of the Part B premium for each full year you delayed, added to your bill for life. If you miss the important date and do not have other health coverage, waiting until the next General Enrollment Period (January 1 to March 31) means your coverage will not start until July 1.

You do not need to be retired to sign up. You become may be able to access at 65 regardless of whether you are still working. If you are still employed and have health coverage through your job, you may be able to delay Part B without penalty — but you must tell Medicare about your work coverage when you sign up.

Key Takeaways

  • Sign up during the seven-month window that starts three months before your 65th birthday, or face a permanent penalty on your premiums.
  • You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or at your local Social Security office — all three routes take about the same time.
  • You will need your Social Security number, proof of citizenship or legal residency, and information about any current health coverage.
  • Part A (hospital insurance) is usually free if you or your spouse paid Medicare taxes for at least 10 years; Part B (medical insurance) costs a monthly premium that varies by income.
  • If you are still working and have employer coverage, tell Medicare when you sign up so you do not pay penalties for delaying Part B.

What documents and information to gather before you sign up

Have your Social Security number ready. Medicare uses this as your identifier throughout the process. You will also need proof that you are a U.S. citizen or lawful permanent resident — a birth certificate, passport, naturalization papers, or permanent resident card all work. If you do not have these documents at home, you can request them from the issuing agency, but this takes time, so start early if your birthday is coming up soon.

Gather information about any health coverage you currently have. If you are still working and covered by your employer's plan, write down the plan name and your employee ID number. If you have coverage through a spouse's job, note that too. If you are on Medicaid or have coverage through the Veterans Administration, have that information ready as well. Medicare needs to know about these because they affect which parts you sign up for and when your coverage starts.

If you have had recent medical care, jot down the names and phone numbers of your doctors. You do not need these to sign up, but you will need them later when you choose a plan, so having them handy saves a step.

The three ways to sign up and what each one involves

Online at Medicare.gov is the fastest route if you are comfortable entering information into a form. Go to Medicare.gov/sign-up-change-plans, answer questions about your citizenship, work history, and current coverage, and submit. You will get a confirmation number on screen. Processing takes about two weeks, and Medicare will mail your card to the address on file with Social Security. This method works 24 hours a day and you can save your progress and come back later if you need to.

By phone at 1-800-MEDICARE (1-800-633-4227) connects you to a Medicare representative who walks you through the same questions. Call times vary by season — during the fall enrollment rush, wait times can be 30 minutes or longer. Have your documents nearby when you call. The representative will confirm your information, answer questions about your coverage options, and give you a confirmation number before you hang up. Processing time is the same as online: about two weeks for your card to arrive.

In person at your local Social Security office works if you prefer to hand over documents and have someone review them on the spot. Find your office at ssa.gov/locator. Bring your Social Security number, proof of citizenship, and information about current coverage. The staff member will fill out the form with you, answer questions, and give you a receipt. This method takes longer in person — expect to spend 30 to 45 minutes — but some people find it clearer to have someone explain the options face to face.

Understanding Part A, Part B, and when each one starts

Part A covers hospital stays, skilled nursing care after a hospital stay, hospice, and home health services. If you or your spouse paid Medicare taxes for at least 10 years, Part A is free — you pay no monthly premium. If you did not work long enough to may have access to, you can still buy Part A, but the premium is around $278 to $556 per month depending on how many years you worked (these amounts change yearly). Part A coverage starts the first day of the month you turn 65, as long as you sign up during your Initial Enrollment Period.

Part B covers doctor visits, outpatient care, medical equipment, and preventive services. Part B requires a monthly premium. The standard premium in 2024 is $174.70 per month, but it is higher if your income is above a certain threshold — Medicare uses your tax return from two years ago to calculate this. Part B coverage also starts the first day of the month you turn 65 if you sign up on time. If you delay Part B because you have employer coverage, you must tell Medicare about that coverage when you sign up, or you will be charged the penalty even though you had a good reason to wait.

If you do not sign up for Part B during your Initial Enrollment Period and you do not have a valid reason to delay (such as current employer coverage), your premium will be 10 percent higher for each full year you waited. This penalty stays on your bill permanently, even after you finally sign up.

What happens after you submit your sign-up information

Medicare processes your sign-up within two weeks. You will receive a confirmation letter in the mail that lists your Medicare number, the date your coverage starts, and which parts you are enrolled in. Your Medicare card arrives separately, usually within two weeks as well, though it can take longer during busy seasons.

Before your coverage starts, you should choose a plan. Medicare Part A and Part B alone do not cover everything — you will have copays, coinsurance, and deductibles. Most people choose either a Medigap plan (supplemental insurance that covers some of the costs Medicare does not) or a Medicare Advantage plan (an alternative to Original Medicare that usually includes prescription drug coverage). You have until December 7 of the year you turn 65 to choose a plan. If you do not choose by then, Medicare will not automatically enroll you in a plan, and you will be responsible for all costs that Medicare does not cover.

If you need prescription drug coverage, sign up for Part D at the same time you sign up for Medicare, or during the same enrollment window. If you delay Part D without having other drug coverage, you will pay a penalty when you finally sign up — 1 percent of the national average premium for each month you waited.

Common mistakes to avoid when signing up

The biggest mistake is missing your Initial Enrollment Period. If you turn 65 and do not sign up within the seven-month window, you will pay a penalty on Part B for the rest of your life. The only exceptions are if you have current employer coverage or if you are a federal employee — in those cases, you have a grace period to sign up without penalty, but you must tell Medicare about your coverage when you do sign up.

Another common error is not telling Medicare about employer coverage. If you are still working and covered by your job, you must report this when you sign up. If you do not, Medicare will charge you the Part B penalty even though you had a valid reason to delay. The penalty applies retroactively, so you end up paying it for months you did not even know you were supposed to avoid it.

Do not assume you are automatically enrolled. Signing up for Medicare is not automatic, even though you have been paying into it through payroll taxes. You must take action. If you are receiving Social Security benefits, you will be automatically enrolled in Parts A and B starting the month you turn 65, but if you are not yet taking Social Security, you must sign up yourself or you will have no coverage.

Finally, do not skip choosing a plan. Many people sign up for Parts A and B and then assume they are done. But Original Medicare leaves you responsible for significant costs. You need to choose either a Medigap plan or a Medicare Advantage plan to cover those gaps. The important date to choose is December 7 of the year you turn 65.

Frequently Asked Questions

What if I am still working at 65 — do I have to sign up for Medicare?

You become may be able to access at 65, but if you have health coverage through your current job, you can delay Part B without penalty. You should still sign up for Part A (hospital insurance) because it is usually free and covers you if you have an accident or emergency. When you sign up, tell Medicare about your employer coverage so the delay is recorded and you do not get charged a penalty later.

Can I sign up for Medicare before I turn 65?

Yes. You can sign up starting three months before your 65th birthday. Your coverage will not start until the first day of the month you turn 65, but signing up early means your card arrives before that date and you avoid the rush. If your birthday is in January, you can sign up starting in October of the previous year.

What if I miss the sign-up important date?

You can still sign up during the General Enrollment Period, which runs January 1 to March 31 each year. However, your coverage will not start until July 1, leaving you uninsured for several months. You will also pay a permanent 10 percent penalty on your Part B premium for each full year you delayed. The only way to avoid this penalty is if you had other health coverage (such as employer insurance) during the time you were not signed up.

Do I need to choose a plan when I sign up for Medicare?

No, but you must choose one before your coverage starts or you will have no plan and will owe all costs out of pocket. You have until December 7 of the year you turn 65 to choose a Medigap or Medicare Advantage plan. If you wait until after that date, you can still choose a plan, but you may not be able to enroll until the next General Enrollment Period.

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

You can sign up for Medicare if you are a lawful permanent resident and have been one for at least five years. You will need to show your permanent resident card (green card) or other proof of legal residency. If you are not a permanent resident, you are not may be able to access for Medicare, though you may be able to purchase private health insurance instead.