Medicare starts the month you turn 65, or the first day of the month after you turn 65

If you were born on the first of any month, your coverage begins that month. If you were born on any other day, coverage starts the first day of the following month. For example, if you turn 65 on March 15, your Medicare coverage begins April 1.

You do not have to wait until your birthday month to prepare. You can start the process three months before you turn 65. This gives you time to understand your options, compare plans, and enroll without rushing.

If you delay enrolling past your 65th birthday, you may face a permanent penalty on your premiums — even if you enroll years later. The only exception is if you have health coverage through a current job (yours or a spouse's). That coverage is considered "creditable coverage," and you can enroll in Medicare without penalty when you leave that job or lose that coverage.

Key Takeaways

  • Medicare coverage begins the month you turn 65, or the first day of the month after your birthday if you were not born on the first.
  • You can enroll starting three months before you turn 65, giving you time to compare Original Medicare, Medicare Advantage, and prescription drug plans.
  • Delaying enrollment past your 65th birthday results in a permanent premium penalty unless you have health coverage through a current job.
  • You must enroll in Part B (medical insurance) and Part D (prescription drug coverage) during your initial enrollment period to avoid penalties.
  • Social Security will automatically enroll you in Part A (hospital insurance) and Part B at 65 if you are already receiving benefits.

Your initial enrollment period: the window to enroll without penalty

Your initial enrollment period is a seven-month window centered on the month you turn 65. It runs from three months before your birthday month through three months after. During this time, you can enroll in Medicare without penalty, even if you do not need coverage right away.

If you miss this window, you will pay a permanent surcharge on Part B premiums (10 percent more for each year you delayed) and on Part D premiums (1 percent more per month you were uninsured). These penalties stay with you for life, so enrolling during your initial period is worth the effort even if you think you do not need it yet.

The only people who can enroll outside this period without penalty are those with creditable coverage through a job. If you have employer health insurance, you have eight months after that coverage ends to enroll in Medicare without penalty.

What happens if you are still working at 65

You are not required to enroll in Medicare at 65 if you have health coverage through your own job or your spouse's job. You can delay Part B enrollment as long as that coverage continues. However, you should still enroll in Part A (hospital insurance) at 65 because it is free and has no penalty for late enrollment.

When you leave your job or lose that coverage, you have eight months to enroll in Part B and Part D without penalty. This is called your Special Enrollment Period. Keep your termination letter or proof of coverage loss, because you will need it to show Medicare that you had creditable coverage.

If you do not enroll within eight months of losing job coverage, you will face the same permanent penalties as someone who delayed from age 65. The clock starts the month your coverage ends, not the month you leave your job, so be precise about the end date.

How to enroll: the three main routes

You can enroll through Medicare.gov, by phone, or in person. Medicare.gov is open year-round, and you can compare plans, see costs, and enroll online. The phone number is 1-800-MEDICARE (1-800-633-4227). Representatives can answer questions and help you enroll over the phone, and they speak many languages.

You can also visit your local Social Security office in person. Bring your birth certificate, proof of citizenship or legal residency, and your driver's license or other ID. Staff there can help you understand your options and enroll in Part A and Part B.

If you are already receiving Social Security benefits at 65, you will be automatically enrolled in Part A and Part B. You will receive a notice in the mail about two months before your 65th birthday. Review it carefully. If you do not want Part B (because you have job coverage, for example), you must decline it in writing before your coverage would start.

Part A, Part B, Part D: what you need to know before enrollment

Part A covers hospital stays, skilled nursing care, hospice, and some home health services. It is free if you or your spouse paid Medicare taxes for at least 10 years. You do not have to enroll in Part A to avoid a penalty — there is no late-enrollment penalty for Part A. However, you should enroll at 65 anyway because it costs nothing and covers hospital care.

Part B covers doctor visits, outpatient care, lab tests, and medical equipment. It has a monthly premium (the amount varies by income) and a yearly deductible. You must enroll in Part B during your initial enrollment period or face a permanent penalty, unless you have creditable job coverage.

Part D is prescription drug coverage. You must enroll during your initial enrollment period or within 63 days of losing job coverage, or you will pay a permanent penalty. Even if you do not take prescription drugs now, enrolling in a plan with no monthly premium keeps you penalty-free if you need drugs later.

You do not have to choose between Original Medicare (Part A and Part B) and Medicare Advantage (Part C). Original Medicare is run by the federal government. Medicare Advantage is run by private insurance companies and includes Part A, Part B, and usually Part D in one plan. If you choose Medicare Advantage, you do not enroll in Original Medicare Part B separately.

What to gather before you enroll

Have your Social Security number, birth date, and citizenship or legal residency information ready. If you are enrolling in Part D or Medicare Advantage, have a list of your current medications and the pharmacies where you fill them. This helps you check whether your drugs are covered and whether your pharmacy is in the plan's network.

If you have other health coverage (from a job, a spouse's job, or COBRA), have that information too. You will need to tell Medicare about it so they know whether you may have access to for a Special Enrollment Period.

If you are enrolling in person at a Social Security office, bring your birth certificate, proof of citizenship or legal residency, and a photo ID. If you are enrolling online or by phone, you will not need to mail documents unless Medicare asks for them later.

After you enroll: what comes next

If you enroll online or by phone, you will receive a Medicare card in the mail within two weeks. If you enroll in person at Social Security, you may receive your card on the spot or by mail within two weeks. Do not throw away your old insurance card until your new Medicare card arrives and your coverage is active.

Your coverage begins on the first day of the month you are may be able to access. If you enroll during your initial enrollment period, your coverage will start on your may be able to access date even if your card has not arrived yet. If you enroll after your initial period (and you have creditable coverage), your coverage starts the first day of the month after you enroll.

Once your coverage is active, you can use your Medicare number to see doctors, fill prescriptions, and access covered services. Keep your Medicare card with you when you see a doctor or go to the hospital. If you chose Medicare Advantage, you will also receive a card from your private insurance company.

Frequently Asked Questions

What if I turn 65 but do not want Medicare yet?

If you have health coverage through your own job or your spouse's job, you do not have to enroll in Part B. You should still enroll in Part A because it is free and has no penalty for late enrollment. When you leave that job or lose that coverage, you have eight months to enroll in Part B without penalty.

Can I change my mind after I enroll?

Yes. You can switch between Original Medicare and Medicare Advantage, or between Part D plans, during the annual open enrollment period (October 15 to December 7). If you enroll in a plan and change your mind within your initial enrollment period, you can switch plans without waiting for open enrollment.

What if I miss my initial enrollment period?

You can still enroll, but you will face a permanent penalty on your Part B and Part D premiums unless you have creditable coverage through a job. The penalty is 10 percent per year for Part B and 1 percent per month for Part D. Enroll as soon as you realize you missed the important date to stop the penalty from growing.

Do I have to enroll in Part D if I do not take any medications?

You are not required to enroll, but it is a good idea. If you enroll in a plan with no monthly premium, you avoid the late-enrollment penalty if you need drugs later. If you wait to enroll until you actually need a drug, you will pay a permanent penalty.

Will Social Security automatically enroll me in Medicare?

If you are already receiving Social Security benefits at 65, yes — you will be automatically enrolled in Part A and Part B. You will receive a notice in the mail about two months before your birthday. If you do not want Part B, you must decline it in writing before your coverage starts.