Medicare Part B covers doctor visits, outpatient care, and medical equipment

Medicare Part B is the part of Medicare that pays for visits to your doctor, outpatient hospital services, lab tests, X-rays, and durable medical equipment like wheelchairs or oxygen. Unlike Part A (hospital insurance), which most people get automatically at 65, you have to take a separate step to enroll in Part B. You can sign up during your Initial Enrollment Period, which runs for seven months starting three months before the month you turn 65.

If you miss that window, you can still sign up later, but you may pay a higher premium for the rest of your life. The amount of the increase depends on how many months you delayed. For that reason, signing up on time matters even if you think you won't need a doctor right away.

Key Takeaways

  • Your Initial Enrollment Period for Part B runs for seven months: three months before you turn 65, the month you turn 65, and three months after.
  • You can sign up online through Medicare.gov, by phone at 1-800-MEDICARE, by mail, or in person at your local Social Security office.
  • Part B coverage begins on the first day of the month after you sign up, or on your 65th birthday if you enroll during your Initial Enrollment Period.
  • If you delay signing up past your Initial Enrollment Period without a valid reason, your monthly premium will be permanently higher.
  • You will receive a bill for your Part B premium each month, and you can choose to pay by mail, automatic bank withdrawal, or credit card.

The three ways to sign up for Part B

You can enroll in Part B through Medicare.gov, by phone, or in person. The online route is fastest: go to Medicare.gov, sign in with your username and password (or create an account), and follow the enrollment steps. You will need your Social Security number and information about any current health insurance you have.

If you prefer to speak with someone, call 1-800-MEDICARE (1-800-633-4227). Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time. They can walk you through the process and answer questions about your coverage. You can also visit your local Social Security office in person to enroll; find the nearest one at ssa.gov.

By mail is slower but works if you are not comfortable online or by phone. Call 1-800-MEDICARE to request an enrollment form, fill it out, and mail it back. Allow extra time for processing if you use this method.

When your Part B coverage starts

Coverage begins on the first day of the month after you sign up—unless you enroll during your Initial Enrollment Period, in which case it can start on your 65th birthday. For example, if you turn 65 on June 15 and enroll in May, your coverage starts June 1. If you turn 65 on June 15 and enroll in July, your coverage starts August 1.

This timing matters because you are responsible for any doctor bills you receive before your Part B coverage begins. If you know you will need medical care soon after turning 65, enroll as early as possible in your Initial Enrollment Period.

What happens if you miss your Initial Enrollment Period

If you do not sign up during your seven-month Initial Enrollment Period, you can still enroll later during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage would then start July 1. However, you will pay a higher monthly premium for as long as you have Part B.

The premium increase is 10 percent for each full 12-month period you were may be able to access but did not enroll. If you delayed for two years, your premium goes up 20 percent. This increase is permanent—it does not go away if you enroll later.

There are exceptions: if you had other health insurance through an employer or union when you turned 65, you may have a Special Enrollment Period that lets you sign up without the penalty. You will need to show proof of that coverage, such as a letter from your employer or a copy of your insurance card.

Your Part B premium and how to pay it

Your monthly Part B premium depends on your income. Most people pay the standard premium, which changes each year. In 2024, the standard premium is $164.90 per month, but this amount increases annually. If your income is higher, you will pay more through a process called Income-Related Monthly Adjustment Amount (IRMAA).

You will receive a bill each month, usually by mail. You can pay by mailing a check, setting up automatic withdrawal from your bank account, or paying by credit or debit card. If you receive Social Security benefits, you can also choose to have your Part B premium deducted directly from your benefit payment.

If you cannot afford the premium, you may be able to get help through Medicaid or other programs. Contact your state Medicaid office or call 1-800-MEDICARE to learn what programs may be available where you live.

What to do after you enroll

After you sign up, Medicare will mail you a Medicare card within two to three weeks. Your card shows your Medicare number and which parts of Medicare you have. Keep this card with you when you go to the doctor or hospital.

Before your coverage starts, make a list of the doctors and hospitals you use and call them to confirm they accept Medicare. Not all providers do. If your current doctor does not accept Medicare, you will need to find one who does, or you will have to pay out of pocket.

You should also think about whether you want to add prescription drug coverage (Part D) or supplemental insurance (Medigap or Medicare Advantage). These decisions have their own enrollment periods and important date. If you have questions about what coverage you need, call 1-800-MEDICARE.

Frequently Asked Questions

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

You may not need to enroll in Part B right away. If your employer has 20 or more employees, your employer coverage is primary and you can delay Part B without penalty. You will have eight months after your employment ends or your coverage stops to enroll without a late penalty. Get a letter from your employer confirming your coverage details to protect yourself.

Can I change my mind after I sign up for Part B?

Yes, but only during certain times. You can drop Part B during the General Enrollment Period (January 1 through March 31), and your coverage ends June 30. If you drop Part B, you cannot re-enroll until the next General Enrollment Period unless you have a may have access to life event, such as loss of employer coverage.

Do I need Part B if I have Medicare Advantage?

Yes. Medicare Advantage (Part C) is an alternative way to receive your Part A and Part B benefits through a private insurance company, but you must be enrolled in both Part A and Part B first. You cannot have Medicare Advantage without Part B.

What if I live outside the United States?

You can enroll in Part B while living abroad, but your coverage generally does not work outside the U.S. except in limited situations, such as emergency care in Canada or Mexico. Talk to Medicare before you move to understand how your coverage will work.

How do I know if my doctor accepts Medicare?

Use the Medicare Provider Search tool at Medicare.gov. Enter your doctor's name or location, and the tool will show whether they accept Medicare and what type of provider they are. You can also call your doctor's office directly and ask.