Medicare Part B is hospital insurance for doctor visits and outpatient care

Medicare Part B covers doctor visits, outpatient hospital services, medical equipment, and preventive care. It is different from Part A, which covers inpatient hospital stays. Part B is optional — you can turn it down — but most people enroll when they turn 65 because the monthly premium is modest and the coverage is broad.

Part B works on a cost-sharing basis: Medicare pays its share, and you pay a monthly premium plus a yearly deductible, then a percentage of each service after that. The exact amounts change each year. You can use any doctor or hospital in the United States that accepts Medicare.

Key Takeaways

  • Part B covers doctor office visits, lab tests, imaging, mental health care, and preventive screenings at no cost to you after you meet your deductible.
  • You pay a monthly premium (the amount varies by income), an annual deductible, and then 20 percent of the cost of most services after the deductible is met.
  • Part B does not cover routine dental, vision, hearing aids, or long-term care — you need separate coverage or out-of-pocket payment for those.
  • If you delay enrolling in Part B past age 65 without other coverage, you may face a permanent penalty on your premium.

What Part B covers: doctor visits and outpatient services

Part B pays for visits to your primary care doctor, specialists, and urgent care clinics. It covers the doctor's time, the office visit fee, and any tests or procedures done in the office. If your doctor orders blood work, an X-ray, or an ultrasound, Part B covers those too — whether they happen in the office or at a separate lab or imaging center.

Part B also covers hospital outpatient services: if you go to a hospital emergency room, get chemotherapy in a hospital cancer center, or have surgery at an outpatient surgical facility, Part B pays its share. Mental health visits — therapy, psychiatry, counseling — are covered the same way as any other doctor visit.

Preventive care is covered at no cost to you after you meet your deductible. This includes annual wellness visits, cancer screenings (mammograms, colonoscopies, Pap tests), heart disease screenings, diabetes screenings, bone density tests, and flu and pneumonia shots. You do not pay the 20 percent coinsurance for these preventive services.

What you pay: premiums, deductibles, and coinsurance

You pay a monthly premium for Part B. The standard premium changes each year; in recent years it has ranged from about $160 to $175 per month, but the amount depends on your income. If you earn more than a certain threshold, you pay a higher premium — Medicare calls this an Income-Related Monthly Adjustment Amount. The Social Security Administration determines your income bracket based on your tax return from two years prior.

You also pay an annual deductible before Medicare starts to pay. Once you have paid the deductible out of pocket, Medicare covers 80 percent of most services and you pay 20 percent. Some preventive services have no deductible and no coinsurance.

There is no yearly cap on what you pay out of pocket under Original Medicare Part B alone. If you have a serious illness or need many doctor visits, your costs can add up. Many people buy a Medigap policy (supplemental insurance) to cover the 20 percent coinsurance and protect against high costs.

What Part B does not cover

Part B does not cover routine dental care, dentures, or tooth extractions. It does not cover routine eye exams, eyeglasses, or contact lenses. Hearing aids and hearing exams are not covered. These are common gaps that many older adults pay for out of pocket or through separate dental and vision insurance plans.

Part B does not cover long-term care — nursing home stays, assisted living, or in-home care aides. It does not cover most prescription drugs (that is Part D). It does not cover cosmetic surgery, weight loss surgery, or fertility treatments. Routine foot care is not covered unless you have diabetes.

If you travel outside the United States, Part B does not cover care you receive abroad, with rare exceptions for emergency care in Canada or Mexico if you are traveling directly between two parts of the United States.

How to enroll in Part B and when enrollment important date matter

Most people enroll in Part B when they first become may be able to access at age 65. You can enroll during your Initial Enrollment Period, which runs for three months before the month you turn 65, the month you turn 65, and three months after. If you enroll during this window, your coverage starts the month you turn 65 (or the first day of the following month if you enroll after your birthday month).

If you miss your Initial Enrollment Period and do not have other health coverage, you can still enroll, but your coverage will start later and you may owe a permanent penalty. The penalty is 10 percent of the standard premium for each full year you were may be able to access but did not enroll. This penalty stays with you for life.

If you are still working and covered by your employer's health plan at 65, 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 without penalty. Keep records of your employer coverage dates.

Part B versus Part A: what is the difference

Part A covers inpatient hospital stays, skilled nursing facility care after a hospital stay, hospice, and some home health care. Part B covers doctor visits and outpatient services. You need both to have full coverage under Original Medicare.

Most people pay a premium for Part B but not for Part A — Part A is free if you or your spouse paid Medicare taxes for at least 10 years. Part B has a monthly premium that everyone pays (adjusted for income). The deductibles and coinsurance are different for each part.

If you choose a Medicare Advantage plan (Part C) instead of Original Medicare, you get both Part A and Part B coverage through a private insurance company, usually with lower out-of-pocket costs but a narrower network of doctors.

Medigap and Medicare Advantage: alternatives to paying 20 percent coinsurance

If you stay in Original Medicare Part B, you will pay 20 percent of most services after your deductible. To reduce this cost, many people buy a Medigap policy — supplemental insurance sold by private insurers that covers the 20 percent coinsurance, the deductible, or both, depending on which plan you choose. Medigap premiums vary widely by plan type and location.

Alternatively, you can enroll in a Medicare Advantage plan (Part C), which is a private insurance plan that covers Part A and Part B services. Medicare Advantage plans often have lower or no deductibles and lower coinsurance, but they limit you to a network of doctors and hospitals, and they may require referrals for specialists.

You cannot have both Medigap and Medicare Advantage at the same time. If you switch from Original Medicare to Medicare Advantage, you may lose the right to buy Medigap without medical underwriting, so the decision is worth thinking through carefully.

Frequently Asked Questions

Do I have to enroll in Part B when I turn 65?

No, Part B is optional. However, if you delay enrollment past your Initial Enrollment Period and do not have other health coverage, you will owe a permanent 10 percent penalty on your premium for life. If you are still working and covered by your employer's health plan, you can delay without penalty.

What happens if I cannot afford the Part B premium?

If your income is low, you may be able to get help paying your Part B premium through your state's Medicare Savings Program. Contact your state Medicaid office or call 1-800-MEDICARE to learn whether you may have access to and how the process works.

Does Part B cover physical therapy?

Yes, Part B covers physical therapy, occupational therapy, and speech-language pathology when ordered by a doctor for a medical condition. You pay 20 percent coinsurance after your deductible. Medicare limits the number of visits per year unless your doctor documents medical necessity.

Can I use any doctor with Part B?

You can see any doctor or hospital in the United States that accepts Medicare. Most do, but it is worth asking before your first visit. If a doctor does not accept Medicare, you may have to pay the full cost out of pocket.

What if I have both Medicare and an employer health plan?

If your employer plan is still active, it is usually your primary insurance and Medicare is secondary. When you retire or lose the employer coverage, enroll in Part B within eight months to avoid a permanent penalty.