Medicare Part B is medical insurance that covers doctor visits, outpatient care, and preventive services

Medicare Part B pays for services from doctors, specialists, and hospital outpatient departments. It covers office visits, lab tests, X-rays, physical therapy, ambulance transport, and durable medical equipment like wheelchairs or oxygen. It also covers preventive care — screenings, vaccines, and annual wellness visits — at no cost to you beyond your Part B premium.

Part B is optional, but most people who have Part A (hospital insurance) also enroll in Part B. You pay a monthly premium for Part B, and you share the cost of most services through a deductible and coinsurance. The amount you pay depends on your income and when you first became may be able to access for Medicare.

Part B does not cover dental, vision, hearing aids, or long-term care. If you need those services, you can buy a separate Medigap policy or a Medicare Advantage plan that may include them.

Key Takeaways

  • Part B covers doctor visits, lab work, imaging, outpatient hospital care, and preventive screenings, but you pay a monthly premium and share costs through a deductible and coinsurance.
  • Preventive services covered by Part B — such as annual wellness visits, cancer screenings, and vaccines — have no copay or coinsurance if you see an in-network provider.
  • Part B does not cover dental, vision, hearing aids, or long-term nursing care, so you may need additional coverage for those services.
  • Your Part B premium is based on your income from two years ago, and higher earners pay a larger share of the cost.

What Part B Actually Covers

Part B covers visits to your primary care doctor and any specialist — cardiologist, rheumatologist, urologist, and so on. It pays for office visits, consultations, and follow-up appointments. If your doctor orders lab work or imaging (X-rays, ultrasounds, CT scans, MRIs), Part B covers those too, as long as they are medically necessary.

Outpatient hospital services are also covered. This means services you receive at a hospital but do not stay overnight for — emergency room visits, same-day surgery, chemotherapy, or dialysis. Part B also covers ambulance transport to a hospital or skilled nursing facility if medically necessary.

Durable medical equipment — canes, walkers, wheelchairs, oxygen equipment, hospital beds — is covered if your doctor prescribes it. You typically pay 20 percent of the cost after you meet your deductible. Part B also covers some home health services, such as skilled nursing or physical therapy, if you are homebound and your doctor orders it.

Preventive Services With No Cost Sharing

One of the strongest benefits of Part B is preventive care. Medicare covers certain screenings and vaccines at no cost to you — meaning no copay, coinsurance, or deductible — if you see a doctor who accepts Medicare assignment (which most do).

These services include an annual wellness visit with your doctor, colorectal cancer screening, mammography, bone density testing, cardiovascular screening, diabetes screening, depression screening, and vaccines for flu, pneumonia, and shingles. The exact list changes, so ask your doctor which preventive services are right for you.

The catch is that the service must be on Medicare's covered list and performed by an in-network provider. If your doctor orders something beyond the standard screening — extra imaging or additional tests — you may owe coinsurance on those add-ons.

How You Pay for Part B Services

You pay for Part B in three ways: a monthly premium, an annual deductible, and coinsurance on each service.

The monthly premium varies based on your income from two years prior. In 2024, the standard premium is $164.90 per month for most people, but if your income was above a certain threshold, you pay more. The income thresholds and premium amounts change each year. Your premium is usually deducted from your Social Security check.

The annual deductible is $240 in 2024 (this amount changes yearly). You pay this amount out of pocket before Part B starts to pay. After you meet the deductible, you typically pay 20 percent coinsurance for most services — your doctor or hospital bills Medicare for 80 percent, and you pay the remaining 20 percent.

There is no out-of-pocket maximum under Original Medicare Part B, which means your costs can add up if you need a lot of care. This is one reason many people buy a Medigap policy to cover the coinsurance and deductible.

Part B Does Not Cover

Part B has clear limits. It does not cover dental work, eye exams for glasses or contacts, or hearing aids. Routine foot care, cosmetic surgery, and weight-loss drugs are not covered. Long-term care — nursing home care or in-home custodial care — is not covered by Part B or any part of Original Medicare.

Prescription drugs are not covered by Part B (with rare exceptions for drugs given in a doctor's office or hospital outpatient setting). If you need prescription coverage, you must enroll in Part D or join a Medicare Advantage plan that includes drug coverage.

If you need services Part B does not cover, you have options. You can buy a Medigap (supplemental) policy to fill some gaps, or you can switch to a Medicare Advantage plan, which often includes dental, vision, and hearing coverage as part of the plan.

When to Enroll in Part B

You become may be able to access for Medicare at age 65. If you are already receiving Social Security, you are automatically enrolled in Part A and Part B. If you are not yet receiving Social Security, you must sign up for Medicare yourself during your Initial Enrollment Period, which is the three months before the month you turn 65, the month you turn 65, and the three months after.

If you miss this window and do not have other health coverage, you may face a late enrollment penalty — a permanent increase to your Part B premium. The penalty is 10 percent of the standard premium for each full year you were may be able to access but did not enroll.

There are exceptions. If you are still working and covered by your employer's health plan, you may be able to delay Part B without penalty. You have eight months after your employment ends or your employer coverage stops to enroll in Part B without penalty. Talk to your employer's benefits office or call Medicare at 1-800-MEDICARE to confirm your situation.

Part B Versus Medicare Advantage

Part B is part of Original Medicare, which is run by the federal government. You can see any doctor or hospital that accepts Medicare. You pay the premiums and cost-sharing amounts set by Medicare.

Medicare Advantage (Part C) is an alternative. Private insurance companies offer these plans, and they must cover everything Part A and Part B cover, but they often add dental, vision, hearing, and fitness benefits. However, Medicare Advantage plans usually have networks — you may have to see doctors within the plan's network, and you may need referrals to see specialists. Premiums and cost-sharing vary by plan.

Neither choice is right for everyone. Original Medicare with Part B gives you more freedom to choose providers. Medicare Advantage may offer more benefits but with less flexibility. Compare plans during the annual enrollment period (October 15 to December 7) to see what works for your health needs and budget.

Frequently Asked Questions

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

Part B is optional, but if you do not enroll when you first become may be able to access and do not have other may have access to coverage, you will pay a permanent penalty on your premium. Most people enroll in Part B, but some who are still working and covered by an employer plan may delay without penalty.

What happens if I see a doctor who does not accept Medicare?

If your doctor does not accept Medicare assignment, you may have to pay the full bill upfront and request reimbursement from Medicare yourself. Some doctors charge more than Medicare allows. Before your visit, ask your doctor's office whether they accept Medicare and at what rate.

Does Part B cover mental health visits?

Yes. Part B covers visits to psychiatrists, psychologists, clinical social workers, and other mental health professionals. You pay the same coinsurance (usually 20 percent after your deductible) as you would for a physical health visit. Preventive mental health screening is also covered at no cost.

Can I use Part B outside the United States?

Original Medicare Part B generally does not cover care outside the U.S., with limited exceptions for emergency care in Canada or Mexico near the border. If you travel internationally, consider buying travel health insurance. Medicare Advantage plans may offer some international coverage, but policies vary by plan.

What is the difference between Part B coinsurance and a copay?

Part B uses coinsurance, which means you pay a percentage (usually 20 percent) of the Medicare-approved amount after you meet your deductible. A copay is a fixed dollar amount per visit. Original Medicare Part B does not use copays; Medicare Advantage plans may offer copays instead of coinsurance.