Part B enrollment windows: the three times you can sign up

You can sign up for Medicare Part B during three separate periods, and the window you use depends on when you turn 65 or become may be able to access through disability. Missing your window can cost you permanently — you will pay a higher premium for as long as you have Part B. The three enrollment periods are your Initial Enrollment Period, the General Enrollment Period, and Special Enrollment Periods that explore only to specific situations.

Your Initial Enrollment Period is a seven-month window that starts three months before the month you turn 65 (or become may be able to access through disability) and ends three months after. If you turn 65 in June, for example, your window opens in March and closes in September. This is the only time you can sign up without a penalty, and it is the time most people should use.

If you do not sign up during your Initial Enrollment Period, you can still sign up during the General Enrollment Period, which runs January 1 through March 31 every year. Coverage begins July 1 of that year. However, you will pay a 10 percent higher premium for each year you delayed signing up — that increase is permanent and stays with you even if you switch plans later.

Key Takeaways

  • Your Initial Enrollment Period is seven months long: three months before, the month of, and three months after you turn 65 or become may be able to access through disability.
  • Signing up during your Initial Enrollment Period costs the standard premium with no penalty.
  • If you miss your Initial Enrollment Period, you can sign up during the General Enrollment Period (January 1 through March 31 each year), but your premium will be 10 percent higher for each year you waited.
  • Special Enrollment Periods allow you to sign up outside the normal windows if you lose employer coverage, move out of your service area, or meet other specific conditions.
  • You must contact Social Security, Medicare, or your employer to sign up; enrollment does not happen automatically when you turn 65.

Your Initial Enrollment Period: the seven-month window

Your Initial Enrollment Period is the easiest and cheapest time to sign up for Part B. It runs for seven months total: three months before the month you become may be able to access, the month itself, and three months after. If you turn 65 in September, your window is June through December. If you become may be able to access through disability at age 62, your seven-month window starts three months before that month of may be able to access.

During this window, you pay the standard Part B premium with no penalty. You can sign up by calling Social Security at 1-800-772-1213, by visiting your local Social Security office, or by going online to ssa.gov. If you are already receiving Social Security benefits, you may be signed up automatically — Social Security will send you a notice explaining your coverage. If you are not yet receiving benefits, you must contact them to enroll.

The key is to sign up early in your window rather than waiting until the last month. If you sign up in June for a September 1 start date, your coverage begins on the first of that month. If you wait until September to sign up, your coverage may not start until October 1, leaving you without Part B coverage for that month.

The General Enrollment Period: signing up late with a penalty

The General Enrollment Period runs January 1 through March 31 every year. Anyone who missed their Initial Enrollment Period can sign up during this window. Coverage begins July 1 of that year, so if you sign up in February, you wait until July to have Part B active.

The trade-off is a permanent premium increase. For each full year you delayed signing up past your Initial Enrollment Period, your Part B premium goes up by 10 percent. If you were supposed to sign up at 65 but did not sign up until age 67, you delayed for two years — your premium will be 20 percent higher than the standard rate. That 20 percent increase stays with you for life, even if you switch Medicare plans or move to a different state.

You can sign up during the General Enrollment Period by calling 1-800-MEDICARE (1-800-633-4227), visiting medicare.gov, or going to your local Social Security office. Have your Social Security number and information about any current health coverage ready when you call.

Special Enrollment Periods: exceptions to the normal windows

A Special Enrollment Period lets you sign up for Part B outside the normal windows without a penalty if you meet specific conditions. The most common reason is losing employer health coverage. If you or your spouse are still working and have group health insurance through that job, you can delay Part B without penalty. When that coverage ends, you have eight months to sign up for Part B without paying the late penalty.

Other situations that open a Special Enrollment Period include moving out of your Medicare service area, losing Medicaid coverage, or having Medicare wrongly deny your initial enrollment. If you believe you may have access to for a Special Enrollment Period, call 1-800-MEDICARE to explain your situation. Medicare staff will tell you whether you may have access to and when your enrollment window closes.

Do not assume you have a Special Enrollment Period just because you missed the regular important date. You must contact Medicare to confirm. If you do not may have access to for a Special Enrollment Period and you sign up late, the 10 percent annual penalty applies.

What happens if you do not sign up on time

If you do not sign up during your Initial Enrollment Period and you do not may have access to for a Special Enrollment Period, you will pay a penalty for the rest of your life. The penalty is 10 percent of the standard Part B premium for each full year you delayed. If you delayed for five years, your premium will be 50 percent higher than someone who signed up on time.

The penalty applies even if you eventually sign up and even if you switch to a different Medicare plan. It does not go away after a certain number of years. The only way to avoid the penalty is to sign up during your Initial Enrollment Period or to may have access to for a Special Enrollment Period.

There is one narrow exception: if you can prove that Medicare or Social Security gave you incorrect information about your enrollment important date, you may be able to get the penalty waived. This requires contacting Medicare directly and providing documentation of the incorrect information. These waivers are rare and require strong evidence.

How to sign up for Part B

You have three main ways to sign up for Part B. The first is to call Social Security at 1-800-772-1213. Have your Social Security number ready. Social Security handles enrollment for people who are not yet receiving Social Security benefits. If you are already receiving benefits, Social Security may enroll you automatically, but you should confirm by checking your notice or calling to verify.

The second way is to call Medicare directly at 1-800-MEDICARE (1-800-633-4227). Medicare staff can answer questions about your coverage and help you enroll. This line is open 24 hours a day, seven days a week.

The third way is online. You can create an account at ssa.gov to manage your Social Security and Medicare enrollment, or you can visit medicare.gov to learn more about Part B and find local enrollment information. Some people prefer calling because they can ask questions in real time, but online enrollment is available if you prefer to sign up that way.

Part B coverage and what it includes

Part B covers doctor visits, outpatient care, medical equipment, and preventive services. It does not cover hospital stays (that is Part A), prescription drugs (that is Part D), or long-term care. Most people need both Part A and Part B to have basic Medicare coverage. Part A is usually free if you or your spouse paid Medicare taxes while working, but Part B requires a monthly premium that changes each year.

When you sign up for Part B, you are also choosing how to receive your coverage. You can stay in Original Medicare (Part A and Part B through the federal government) or switch to a Medicare Advantage plan (Part C), which is an alternative way to receive your Part A and Part B benefits through a private insurance company. Your enrollment choices affect both your coverage and your costs, so it is worth understanding the difference before you sign up.

Frequently Asked Questions

What if I turn 65 but I am still working and have employer health insurance?

You can delay Part B without penalty as long as you have group health insurance through your job or your spouse's job. When that coverage ends, you have eight months to sign up for Part B without paying the late penalty. Contact Medicare to confirm your Special Enrollment Period dates.

Do I get signed up for Part B automatically when I turn 65?

Not always. If you are already receiving Social Security benefits, you are usually signed up automatically. If you are not receiving Social Security, you must contact Social Security or Medicare to enroll. Check your mail for a notice from Social Security explaining your coverage, or call 1-800-772-1213 to confirm whether you are enrolled.

Can I sign up for Part B in the middle of the year?

Only during the General Enrollment Period (January 1 through March 31) or if you may have access to for a Special Enrollment Period. If you miss both, you must wait until the next General Enrollment Period. There is no mid-year enrollment outside these windows.

How much does Part B cost?

The standard Part B premium changes each year. In 2024, the standard premium is $164.90 per month, but it varies based on your income and whether you signed up on time. If you delayed signing up, your premium will be higher. Contact Medicare for the current premium amount.

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

Late penalties are applied automatically and are difficult to remove. You can contact Medicare to request a waiver if you can prove that Medicare or Social Security gave you wrong information about your important date, but waivers are rare. It is better to sign up during your Initial Enrollment Period to avoid the penalty altogether.