Sign-Up Windows for Medicare Part B

You can sign up for Medicare Part B during three different periods, and which one applies to you depends on when you turn 65 and whether you have other health coverage. The main window is your Initial Enrollment Period, which runs for seven months: the three months before the month you turn 65, the month you turn 65, and the three months after. If you miss this window, you can sign up during the General Enrollment Period from January 1 to March 31 each year, but you may pay a penalty for every month you waited. A third option, Special Enrollment Period, lets you sign up outside the normal windows if you have employer coverage or certain other circumstances.

The month your coverage starts depends on when you sign up. If you enroll during your Initial Enrollment Period, coverage typically begins the first day of the month you turn 65 or the first day of the following month, depending on your birth date. If you enroll during General Enrollment Period, coverage starts July 1 of that year. Knowing your specific window matters because signing up late can cost you more in premiums for the rest of your life.

Key Takeaways

  • Your Initial Enrollment Period is seven months long: three months before you turn 65, the month you turn 65, and three months after.
  • If you miss your Initial Enrollment Period, you can sign up during General Enrollment Period (January 1 to March 31 each year), but you will pay a higher premium.
  • Part B coverage that starts during your Initial Enrollment Period begins on the first or second day of the month you turn 65, depending on your birth date.
  • If you have employer health coverage when you turn 65, you may be able to delay Part B without penalty through Special Enrollment Period.

Your Initial Enrollment Period: The Seven-Month Window

Your Initial Enrollment Period is the easiest and least expensive time to sign up for Part B. It starts three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your window opens in March and closes in September. You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

During this window, you will not face a late-enrollment penalty even if you do not sign up right away. However, your coverage start date depends on when you enroll. If you sign up before the month you turn 65, coverage usually starts the first day of the month you turn 65. If you sign up in the month you turn 65 or later, coverage typically starts the first day of the following month. This timing matters if you have a gap in coverage or want to avoid overlapping with another plan.

Most people should sign up during this period. If you are already receiving Social Security benefits, Medicare will contact you automatically about three months before you turn 65. If you are not yet receiving Social Security, you will need to contact Medicare yourself to enroll.

General Enrollment Period: The Backup Window

If you miss your Initial Enrollment Period, General Enrollment Period runs from January 1 to March 31 each year. You can sign up during this window through Medicare.gov, by phone, or at your local Social Security office. Coverage begins July 1 of that year, which means there is a gap between when you sign up and when coverage starts.

The trade-off is cost. For every full 12-month period you delayed Part B after your Initial Enrollment Period ended, your monthly premium increases by 10 percent. This increase is permanent — it stays with you for life, even if you switch plans later. If you waited three years to sign up, your premium would be 30 percent higher than the standard amount. Over a 20-year retirement, this penalty can add up to thousands of dollars.

General Enrollment Period is a safety net, not a preferred route. Use it only if you genuinely could not sign up during your Initial Enrollment Period.

Special Enrollment Period: Exceptions to the Rules

Special Enrollment Period lets you sign up for Part B outside the normal windows without facing a late-enrollment penalty. The most common reason is having employer health coverage when you turn 65. If you or your spouse is still working and covered by an employer plan, you can delay Part B and sign up later without penalty. You have eight months after your employment ends or your employer coverage stops to enroll in Part B.

Other situations that trigger Special Enrollment Period include losing Medicaid coverage, moving out of your Medicare plan's service area, or having Medicare wrongly deny your initial claim. If any of these explore to you, contact Medicare directly to confirm your window and sign-up important date. The rules vary by situation, and missing the important date can still result in a penalty.

If you have employer coverage, do not assume you should skip Part B. Talk to your employer's benefits office about whether Part B is required under your plan. Some employers require retirees to enroll in Part B even while still covered by the employer plan.

What Happens If You Miss All important date

If you do not sign up during your Initial Enrollment Period and you do not have a Special Enrollment Period available, you must wait for the next General Enrollment Period. During that wait, you have no Part B coverage unless you have other insurance. If you go without any coverage, you risk owing the full cost of doctor visits, lab work, and hospital care out of pocket.

When you finally do sign up during General Enrollment Period, your premium penalty begins when ready and lasts for life. The penalty is 10 percent of the standard Part B premium for each full 12-month period you delayed. If the standard premium is $165 per month and you waited two years, your premium would be about $198 per month permanently. Over 20 years, that adds up to nearly $8,000 in extra costs.

The only way to avoid this penalty after missing your Initial Enrollment Period is to have had a valid reason covered by Special Enrollment Period. If you think you had a may have access to reason, contact Medicare to ask about it — they can review your situation.

How to Sign Up for Part B

You have three ways to enroll in Part B. Online is the fastest: go to Medicare.gov, log in or create an account, and follow the enrollment steps. You can complete it in about 10 minutes. 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. In person, visit your local Social Security office with your Medicare card and identification.

Have your information ready before you start: your Social Security number, date of birth, and current contact information. If you are signing up during your Initial Enrollment Period, you can enroll as soon as you are three months away from turning 65. If you are signing up during General Enrollment Period, you can enroll anytime between January 1 and March 31.

After you enroll, Medicare will send you a confirmation letter and your new Medicare card within two to three weeks. Your coverage start date will be listed on that letter. If you do not receive it within three weeks, call 1-800-MEDICARE to check the status.

Part B Premium and Coverage Details

The standard Part B premium changes each year. In 2024, the standard premium is $165 per month for most people, though higher earners pay more through an income-related adjustment. Your actual premium may be different depending on your income and when you enroll. If you enroll late, your premium will be higher by the penalty percentage described above.

Part B covers doctor visits, outpatient hospital care, medical equipment, and some preventive services. It does not cover dental, vision, or hearing care. Most people pair Part B with either a Medigap plan (supplemental insurance) or a Medicare Advantage plan (an alternative to Original Medicare). Your choice of plan does not affect when you can sign up for Part B itself, but it does affect your total out-of-pocket costs.

Frequently Asked Questions

What if I turn 65 but am not ready to retire?

You still need to make a choice about Part B. If your employer covers you, you may be able to delay Part B without penalty through Special Enrollment Period. If you do not have employer coverage, you should sign up during your Initial Enrollment Period to avoid a permanent premium penalty. Contact your employer's benefits office to understand your options.

Can I sign up for Part B in the month I turn 65?

Yes. Your Initial Enrollment Period includes the month you turn 65. If you sign up in that month, coverage typically starts the first day of the following month. If you sign up before that month, coverage usually starts the first day of the month you turn 65.

What if I was working and missed my Initial Enrollment Period?

If you had employer coverage when you turned 65, you may have a Special Enrollment Period that lasts eight months after your employment or coverage ends. Contact Medicare to confirm whether this applies to you. If it does, you can sign up without penalty during that window.

Do I have to sign up for Part B if I have a Medicare Advantage plan?

Yes. Medicare Advantage is an alternative way to receive Part B benefits, not a replacement for signing up. You must be enrolled in both Part A and Part B to join a Medicare Advantage plan. You sign up for Part B during your Initial Enrollment Period, then choose your Medicare Advantage plan during the annual open enrollment period.

How much will the late-enrollment penalty cost me?

The penalty is 10 percent of the standard Part B premium for each full 12-month period you delayed after your Initial Enrollment Period ended. The standard premium changes yearly. If you delayed two years, your premium would be 20 percent higher than standard, and that increase stays with you for life.