When to Register for Medicare: Timing and Deadlines

Register During Your Initial Enrollment Period or Face Penalties

You can register for Medicare starting three months before the month you turn 65. Most people register during their Initial Enrollment Period, which runs for seven months total: three months before the month you turn 65, the month you turn 65, and three months after. If you miss this window, you will pay a permanent penalty on your premiums for as long as you have Medicare — even if you register years later.

The penalty is 10 percent of the Part B premium for each full year you could have had coverage but did not. For Part D (prescription drug coverage), the penalty is 1 percent of the national base premium for each month you went without it. These penalties do not go away, so timing your registration correctly matters financially.

If you are still working at 65 and have health coverage through your employer, you may have a different enrollment window. Talk to your employer's benefits office before you turn 65 to learn whether you can delay registration without penalty.

Key Takeaways

You can register for Medicare three months before you turn 65, and you have until three months after your birthday to register without penalty.
Missing your Initial Enrollment Period results in a permanent 10 percent premium penalty for Part B and a 1 percent monthly penalty for Part D.
If you have health coverage through your current employer, you may be able to delay registration without penalty — check with your employer's benefits office first.
You register through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
Part A (hospital insurance) is usually automatic if you receive Social Security, but you still need to register for Part B and Part D separately.

How to Register During Your Initial Enrollment Period

Start by going to Medicare.gov and creating an account. You will need your Social Security number, date of birth, and contact information. The site walks you through choosing Part B (medical insurance) and Part D (prescription drug coverage). You can also call 1-800-MEDICARE and speak to someone who will help you register over the phone, or visit your local Social Security office in person.

If you are already receiving Social Security benefits, Part A is usually enrolled automatically. You will receive a Medicare card in the mail about two weeks after you register. Check it carefully — if your name, date of birth, or Social Security number is wrong, contact Medicare right away to correct it.

The important date to register without penalty is the last day of the third month after the month you turn 65. For example, if you turn 65 in June, your important date is September 30. Mark this date on your calendar or set a phone reminder three months before your birthday.

What Happens If You Miss Your Initial Enrollment Period

If you do not register during your seven-month Initial Enrollment Period, you enter a General Enrollment Period that runs from January 1 to March 31 each year. You can register during this window, but coverage does not start until July 1 of that year. This means if you miss your Initial Enrollment Period in September and do not register until February, you will have no Medicare coverage from October through June.

You will also owe the permanent penalty. For Part B, this is 10 percent of the standard premium for each 12-month period you were may be able to access but not enrolled. For Part D, it is 1 percent of the national base premium for each month you were without coverage. These penalties are calculated and added to your premium every month you have Medicare.

The only exception is if you had other health coverage that counted as "creditable coverage" — meaning it was at least as good as Medicare. If you can prove you had employer coverage or another plan that covered prescription drugs, you may avoid the Part D penalty. You will need to provide documentation from your former plan.

Special Enrollment Periods for Life Changes

If you experience certain life events, you may have a Special Enrollment Period that lets you register outside the normal windows. These events include losing employer health coverage, moving to a different state, getting married, or having a significant change in income.

A Special Enrollment Period usually lasts two months from the date of the event. For example, if you lose your job and your employer health coverage in October, you have until the end of December to register for Medicare without penalty. You will need to document the event — keep your termination letter, proof of loss of coverage, or other paperwork that shows what happened and when.

Call 1-800-MEDICARE to report a life change and ask whether you may have access to for a Special Enrollment Period. Do not wait — the two-month window is strict, and missing it means you go back to the standard General Enrollment Period rules.

Registering If You Are Not Yet Receiving Social Security

If you are turning 65 but have not started collecting Social Security, you still need to register for Medicare separately. Part A is not automatic unless you are already receiving Social Security or Railroad Retirement benefits. You must register for Part A, Part B, and Part D yourself through Medicare.gov, by phone, or at your local Social Security office.

Even if you plan to delay Social Security to get a higher benefit later, register for Medicare at 65. There is no financial penalty for registering for Medicare early, and you avoid the permanent premium penalties that come with late registration. You can always choose to delay Social Security while keeping Medicare active.

Registering If You Are Still Working at 65

If you are still working and have health coverage through your employer, you may be able to delay Part B registration without penalty. This is called creditable coverage. You must have a group health plan based on your current employment — coverage from a spouse's employer usually does not count.

Contact your employer's benefits office and ask whether your plan is creditable coverage. If it is, you can delay Part B and Part D registration. When you do register later, you will not owe the permanent penalty. However, you must register within eight months of leaving your job or losing the employer coverage, or the penalty kicks in.

Part A is different — you can delay it without penalty as long as you have employer coverage based on current employment. But once you stop working or lose that coverage, you have a limited window to register for Part A without penalty.

What to Have Ready When You Register

Gather these documents before you start the registration process: your Social Security number, date of birth, citizenship or immigration status, current mailing address, phone number, and email address. If you are registering by phone or in person, have your health insurance information available so you can tell Medicare about any current coverage.

If you are registering for Part D (prescription drug coverage), have a list of the medications you take. This helps you compare plans and choose one that covers your drugs at the lowest cost. You can also compare plans on Medicare.gov without registering — the site has a tool that shows you what each plan costs for your specific medications.

If you are registering because you lost employer coverage or experienced a life change, have documentation of that event ready. This might be a termination letter, proof of loss of coverage, or a notice from your former plan.

Frequently Asked Questions

Can I register for Medicare before I turn 65?

Yes. You can register starting three months before the month you turn 65. For example, if your birthday is in June, you can register starting in March. This is the best time to register because it gives you the longest window to complete the process without rushing.

What if I turn 65 in the middle of a month?

Your Initial Enrollment Period is based on the month you turn 65, not the specific date. If you turn 65 on June 15, your enrollment period runs from March through September. Your coverage can start as early as the first day of the month you turn 65, depending on when you register.

Do I have to register for Part B if I do not want it?

You do not have to register for Part B, but if you decline it and change your mind later, you will owe a permanent penalty unless you had creditable coverage. If you are still working and have employer coverage, you can decline Part B without penalty as long as you register within eight months of losing that coverage.

What if I registered late but did not know about the penalty?

The penalty applies whether you knew about it or not. However, you can request a waiver if you can show that Medicare or Social Security gave you incorrect information that caused you to miss your important date. Contact Medicare at 1-800-MEDICARE to ask about a waiver.

Can I change my Medicare plan after I register?

Yes. You have an annual window called Open Enrollment that runs from October 15 to December 7 each year. During this time, you can switch Part B plans, Part D plans, or both. You can also make changes if you experience a may have access to life event like moving, losing coverage, or getting married.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.