Medicare Part B is the medical insurance portion of Original Medicare

Medicare Part B covers doctor visits, outpatient care, medical equipment, and preventive services. It is sometimes called "medical insurance" to distinguish it from Part A (hospital insurance). Part B is optional — you do not have to take it — but most people do because the cost is low and the coverage is broad.

Part B works alongside Part A. While Part A pays for hospital stays, skilled nursing facilities, and hospice, Part B pays for the things that happen outside the hospital: your primary care doctor, specialists, lab tests, X-rays, wheelchairs, oxygen, and vaccines. Together, Parts A and B make up Original Medicare, the traditional fee-for-service program run by the federal government.

You pay a monthly premium for Part B (the amount changes each year based on your income). You also pay a yearly deductible, then a percentage of the cost for most services. The program is available to anyone 65 or older, and to some younger people with disabilities or end-stage renal disease.

Key Takeaways

  • Medicare Part B covers doctor visits, outpatient procedures, lab work, imaging, and medical equipment — anything that is not a hospital stay.
  • Part B is optional, but if you delay signing up without a valid reason, you may pay a permanent penalty on your premium.
  • You pay a monthly premium (income-based for higher earners), an annual deductible, and then coinsurance on most services.
  • Part B works with Part A to form Original Medicare; it does not include prescription drugs, which are covered under Part D.
  • You can use any doctor or provider who accepts Medicare, anywhere in the United States.

What Part B covers and what it does not

Part B covers doctor office visits, whether for a routine checkup or a specific problem. It pays for specialist visits — cardiologists, orthopedists, dermatologists — as long as they accept Medicare. It covers lab tests ordered by your doctor, imaging like X-rays and MRI scans, and outpatient surgery at a hospital or surgery center.

Part B also covers medical equipment and supplies: wheelchairs, walkers, oxygen, diabetic testing supplies, and hearing aids (as of 2023). It pays for preventive services with no cost to you, including annual wellness visits, cancer screenings, cardiovascular screenings, and most vaccines. Mental health services, including therapy and psychiatric visits, are covered.

Part B does not cover prescription drugs — that is Part D. It does not cover dental work, vision exams, eyeglasses, or hearing aids fitted by an audiologist (though the device itself may be covered). It does not cover long-term care, custodial care in a nursing home, or routine foot care. Cosmetic surgery is not covered unless it is medically necessary after an injury or illness.

How much Part B costs

The monthly premium for Part B varies by year and by income. For 2024, the standard premium is $164.90 per month for most people, but higher earners pay more. If your modified adjusted gross income is above a certain threshold (the amount changes yearly), you pay an additional amount called an Income-Related Monthly Adjustment Amount (IRMAA).

You also pay an annual deductible — $240 for 2024 — before Part B starts to pay. After you meet the deductible, you typically pay 20 percent of the cost for most services, and Part B pays 80 percent. For some preventive services, you pay nothing at all.

If you have a Medigap or Medicare Advantage plan, your out-of-pocket costs may be different. Medigap plans help pay your deductible and coinsurance. Medicare Advantage plans (Part C) replace Part B entirely and often have lower premiums but higher out-of-pocket costs per visit.

When to sign up for Part B

You become may be able to access for Medicare at 65. Your Initial Enrollment Period runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. If you sign up during this window, your coverage starts the month you turn 65 (or the first day of the month you turn 65 if you were born on the first of the month).

If you miss your Initial Enrollment Period and do not have other coverage, you can still sign up, but your premium will be higher. You will pay a permanent 10 percent penalty for each 12-month period you were not enrolled. This penalty stays with you for life, so signing up late is expensive.

There are exceptions: if you were covered by an employer plan while working, or if you are still working and covered by your employer, you may be able to delay Part B without penalty. You have eight months after your employment ends or your employer coverage stops to sign up without penalty.

Part B versus Medicare Advantage and Medigap

Original Medicare Part B is one way to get coverage, but it is not the only way. Medicare Advantage (Part C) is an alternative offered by private insurance companies. It includes Part B coverage, usually with a lower or zero premium, but it typically requires you to use doctors in a network and may have higher copays per visit.

If you stay with Original Medicare Part B, you can buy a Medigap policy (also called Supplemental Insurance) from a private insurer to cover the costs Part B does not — your deductible, coinsurance, and copays. Medigap plans are standardized, so Plan G from one company covers the same things as Plan G from another.

The choice between Original Medicare with Medigap and Medicare Advantage depends on your health, your doctors, and your budget. Original Medicare lets you see any doctor anywhere, but you pay more out of pocket unless you have Medigap. Medicare Advantage has lower premiums but limits your choice of providers.

How to use Part B once you are enrolled

Once Part B is active, you receive a Medicare card in the mail. Show this card to your doctor or provider. Most doctors accept Medicare, but not all — ask before your first visit. Your doctor's office will bill Medicare directly for the visit. You will receive an Explanation of Benefits (EOB) in the mail showing what Medicare paid and what you owe.

You do not need a referral to see a specialist under Part B — you can call any specialist who accepts Medicare and make an appointment. If you need imaging or lab work, your doctor orders it and sends it to a facility that accepts Medicare. You are responsible for paying your share (usually 20 percent after the deductible) once the provider bills you.

Keep copies of your EOBs and bills. If you see a charge you do not recognize or think Medicare paid incorrectly, you can file an appeal. Medicare has a formal process for this, and you have 120 days from the date on the EOB to start.

Part B and prescription drugs

Part B does not cover prescription medications you take at home. For that coverage, you need Medicare Part D, a separate prescription drug plan. Part D is optional but recommended — if you go without it and later sign up, you may pay a permanent penalty on your premium, similar to Part B.

Part D is offered by private insurance companies and varies in cost and which drugs it covers. You choose a Part D plan during your Initial Enrollment Period or during the annual Open Enrollment Period (October 15 to December 7). If you have Original Medicare Part B, you can add Part D at any time.

Some medications given as injections in a doctor's office or hospital outpatient setting are covered by Part B, not Part D. Your doctor's office will know which category applies to your medication.

Frequently Asked Questions

Do I have to take Medicare Part B when I turn 65?

No, Part B is optional. However, if you delay signing up without valid coverage from an employer or other source, you will pay a permanent 10 percent premium penalty for each year you were not enrolled. Most people sign up to avoid this penalty.

Can I use any doctor with Medicare Part B?

Yes, you can see any doctor or specialist who accepts Medicare, anywhere in the United States. You do not need a referral. However, not all providers accept Medicare, so call ahead to confirm before scheduling an appointment.

What is the difference between Part B and Medicare Advantage?

Part B is Original Medicare — you pay a monthly premium and then 20 percent of costs after your deductible. Medicare Advantage (Part C) is a private plan that includes Part B coverage, usually with lower premiums but higher copays and network restrictions. Both cover the same basic services.

Does Part B cover my prescriptions?

No. Part B covers medications given in a doctor's office or hospital, but not pills you take at home. You need Medicare Part D for prescription drug coverage. Part D is a separate plan you choose from private insurers.

What happens if I miss my enrollment important date for Part B?

You can still sign up later, but you will pay a permanent 10 percent penalty on your monthly premium for each 12-month period you were not enrolled. This penalty lasts for life. If you had employer coverage when you turned 65, you have eight months after that coverage ends to sign up without penalty.