Where and How to Enroll in Medicare

You enroll in Medicare through Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. The process itself is straightforward: you provide your name, Social Security number, date of birth, and citizenship information. Medicare then determines which parts you are may have access to to based on your age and work history.

Most people become may be able to access at 65. If you are already receiving Social Security benefits, Medicare will contact you automatically about three months before your 65th birthday. If you are not yet receiving Social Security, you will need to contact Medicare yourself to start the enrollment process. The enrollment window is seven months long—three months before the month you turn 65, the month itself, and three months after.

Online enrollment through Medicare.gov is the fastest route. You can create an account, answer the may be able to access questions, and submit your information in about 15 minutes. Phone enrollment takes longer because you will speak to a representative, but it is useful if you have questions during the process or do not have internet access.

Key Takeaways

  • You can enroll through Medicare.gov, by calling 1-800-MEDICARE, or at your local Social Security office, and the process takes 15 minutes to an hour depending on the method.
  • Your enrollment window is seven months long—three months before you turn 65, the month of your birthday, and three months after—and missing it can mean permanent late penalties.
  • If you are already receiving Social Security, Medicare will contact you automatically; if not, you must contact Medicare yourself to start enrollment.
  • Part A (hospital insurance) and Part B (doctor visits) are the two main parts most people enroll in, though you can choose Part A only if you prefer.
  • Enrollment is free, and coverage typically begins the first day of the month you turn 65 or the first day of the month after you enroll, whichever is later.

Understanding Part A and Part B at Enrollment

When you enroll, you will choose between Part A, Part B, or both. Part A covers hospital stays, skilled nursing facility care, and some home health services. Part B covers doctor visits, outpatient care, and preventive services. Most people enroll in both because they work together—Part A covers the hospital bed, Part B covers the doctor who treats you in that bed.

Part A is usually free if you or your spouse paid Medicare taxes for at least 10 years while working. Part B has a monthly premium that changes each year; in 2024 it ranges from $174.70 to $610.50 per month depending on your income. You will pay this premium whether you use Medicare or not, so delaying Part B enrollment to save money usually backfires—you will owe a penalty of 10 percent per year for every year you delayed, and that penalty is permanent.

If you are still working at 65 and have health insurance through your employer, you may be able to delay Part B without penalty. This is called the Special Enrollment Period, and it requires that your employer has at least 20 employees and that you are actively employed. You will need to provide proof of employer coverage when you enroll later.

Choosing Between Original Medicare and Medicare Advantage

After you enroll in Part A and Part B, you will decide whether to stay with Original Medicare (the federal program run by Medicare) or switch to a Medicare Advantage plan (a private insurance plan that covers everything Original Medicare does, plus usually dental, vision, and hearing). This choice is separate from enrolling in Parts A and B—you must enroll in those first.

Original Medicare lets you see any doctor or hospital that accepts Medicare, with no network restrictions. You will pay a deductible and coinsurance (a percentage of the cost) for each service. Most people with Original Medicare also buy a Medigap policy, which is supplemental insurance that covers the deductibles and coinsurance Medicare does not pay.

Medicare Advantage plans have lower or zero monthly premiums but require you to use doctors and hospitals in their network, except in emergencies. They also have out-of-pocket maximums—once you spend that amount, the plan covers everything else for the rest of the year. If you choose Medicare Advantage, you do not need Medigap.

You do not have to decide between Original Medicare and Medicare Advantage during your initial enrollment. You can enroll in Original Medicare first and switch to Medicare Advantage later during the annual enrollment period (October 15 to December 7 each year).

Adding Prescription Drug Coverage (Part D)

Part D is prescription drug coverage, and it is optional but important. If you do not enroll in Part D when you first become may be able to access, you will owe a penalty of about 1 percent of the national average drug plan premium for every month you go without it. That penalty is permanent and added to your monthly premium for as long as you have Medicare.

You can enroll in Part D at the same time you enroll in Parts A and B, or you can add it later during the annual enrollment period. Part D plans vary widely in cost and which drugs they cover, so comparing plans before you choose is worth the time. You can compare plans on Medicare.gov by entering the medications you take—the site will show you which plans cover them and what your costs will be.

If you have a Medicare Advantage plan, prescription drug coverage is usually included, so you do not need to enroll in Part D separately. Check your plan documents to confirm.

What Happens After You Enroll

After you submit your enrollment information, Medicare will send you a confirmation letter in the mail within two weeks. This letter will tell you your coverage start date, your Medicare number, and which parts you enrolled in. Keep this letter—you will need your Medicare number for doctor visits and prescriptions.

Your Medicare card will arrive in the mail about two weeks after your coverage starts. Until it arrives, you can use the confirmation letter as proof of coverage. If you enrolled online or by phone, you can also print your coverage information from Medicare.gov.

Your coverage typically begins on the first day of the month you turn 65, or the first day of the month after you enroll, whichever is later. If you enroll before the 15th of a month, coverage usually starts the first of that month. If you enroll on the 15th or later, coverage usually starts the first of the next month.

Common Mistakes to Avoid During Enrollment

The biggest mistake is missing your enrollment window. If you turn 65 and do not enroll within seven months, you will owe a permanent penalty on Part B and Part D premiums. The only exceptions are if you are still working with employer coverage, or if you are a federal employee with federal employee health benefits—both allow you to delay without penalty.

Another common mistake is not comparing Part D plans before enrolling. Drug plans change their formularies (the list of drugs they cover) and costs every year, so the plan that was cheapest last year may not be this year. Spending 20 minutes comparing plans on Medicare.gov can save you hundreds of dollars annually.

A third mistake is enrolling in Medicare Advantage without understanding the network. If your doctor is not in the plan's network, you will have to switch doctors or pay out-of-network rates. Before you enroll, call the plan and confirm that your current doctors and preferred hospital are in-network.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65?

No, you cannot enroll before 65 unless you have been receiving Social Security disability benefits for at least 24 months, or you have end-stage renal disease or ALS. If either of those applies, Medicare will contact you automatically. Otherwise, your enrollment window opens three months before your 65th birthday.

What if I miss my enrollment important date?

You can still enroll after your seven-month window closes, but you will owe a permanent penalty on Part B and Part D premiums. The penalty is 10 percent per year for every year you delayed. You can enroll during the general enrollment period (January 1 to March 31 each year), and coverage will start July 1.

Do I have to enroll in Part B if I am still working?

If your employer has at least 20 employees and you are actively employed, you can delay Part B without penalty. You will need to provide proof of employer coverage when you enroll later. Once you stop working or lose employer coverage, you have eight months to enroll in Part B without penalty.

Can I change my mind after I enroll?

Yes. If you enrolled in Original Medicare, you can switch to Medicare Advantage during the annual enrollment period (October 15 to December 7). If you enrolled in Medicare Advantage, you can switch back to Original Medicare during the same period. Changes take effect January 1 of the following year.

Is there a cost to enroll in Medicare?

No, enrollment itself is free. You will pay premiums for Part B and Part D, and possibly for a Medigap or Medicare Advantage plan, but the act of enrolling costs nothing. If you enroll online or by phone, there are no process fees.