What Part B Covers and What You Pay

Part B is the portion of Original Medicare that pays for doctor visits, outpatient care, and certain medical equipment and services. It covers your visits to doctors' offices, hospital outpatient departments, urgent care centers, and labs. Part B does not cover hospital stays — that is Part A — and it does not cover prescription drugs, which require Part D.

You pay for Part B in two ways: a monthly premium (the amount most people pay) and a share of the cost when you use services. The monthly premium amount depends on your income. If you earned less than a certain threshold in the past two years, you pay the standard premium. If you earned more, you pay a higher amount called an Income-Related Monthly Adjustment Amount, or IRMAA.

When you use a covered service, you typically pay a deductible first — a set amount you must pay out of pocket before Part B starts to help. After you meet the deductible, you usually pay 20 percent of the cost for most services, and Medicare pays 80 percent. Some services, like preventive care visits and screenings, have no cost-sharing at all.

Key Takeaways

  • Part B covers doctor visits, outpatient procedures, lab tests, imaging, and certain medical equipment, but not hospital stays or prescription drugs.
  • You pay a monthly premium based on your income, plus a deductible and 20 percent coinsurance for most services after the deductible is met.
  • Preventive services like annual wellness visits and cancer screenings are fully covered with no deductible or coinsurance.
  • You must see doctors who accept Medicare assignment to get the standard cost-sharing; out-of-network doctors may charge more.
  • Part B coverage works the same whether you have Original Medicare alone or Original Medicare paired with a Medigap or Medicare Advantage plan.

When Part B Starts and How to Enroll

Part B coverage begins the month you turn 65, but only if you enroll during your Initial Enrollment Period. This period runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after. If you do not enroll during this window and you do not have other health coverage, you will face a permanent penalty on your monthly premium — 10 percent more for each full year you delayed.

You enroll in Part B through Social Security, either online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office. You will need your Social Security number and information about any current health coverage. If you are still working and covered by your employer's health plan, you may be able to delay Part B without penalty, but you must tell Social Security that you are doing so.

If you miss your Initial Enrollment Period, you can enroll during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage would begin July 1 of that year. However, the 10 percent penalty applies for each year you were may be able to access but not enrolled.

How Deductibles and Coinsurance Work

Each calendar year, Part B has a deductible — a dollar amount you must pay for covered services before Medicare begins to share the cost. Once you meet the deductible, Medicare pays 80 percent of the approved amount for most services, and you pay 20 percent. The deductible amount changes each year and is set by Medicare.

The approved amount is what Medicare decides a service is worth, not necessarily what the doctor charges. If your doctor accepts Medicare assignment, they agree to charge only the approved amount. If they do not accept assignment, they can charge up to 15 percent more than the approved amount — you would owe that extra amount on top of your 20 percent coinsurance.

Some services have different cost-sharing rules. Preventive services — like your annual wellness visit, cancer screenings, and certain vaccines — are covered at 100 percent with no deductible. Mental health visits are covered at 80 percent after the deductible, the same as other services. Therapy and rehabilitation services may have limits on the number of visits Medicare will cover in a year.

Original Medicare Versus Medicare Advantage

Part B is the same whether you choose Original Medicare or Medicare Advantage. The difference is in how you use it. With Original Medicare, you have Part B coverage, and you can see any doctor who accepts Medicare. With Medicare Advantage, you still have Part B, but the insurance company manages your benefits — you typically must use doctors in their network, and your out-of-pocket costs may be different.

If you have Original Medicare alone, you pay the Part B premium, deductible, and coinsurance directly to doctors and providers. Many people add a Medigap policy to help cover the deductible and coinsurance. If you have Medicare Advantage, the insurance company collects the Part B premium on your behalf, and you pay the plan's deductible and copays instead of the standard 20 percent coinsurance.

Regardless of which path you choose, Part B covers the same services. The choice affects which doctors you can see, how much you pay out of pocket, and whether you need a separate prescription drug plan.

What Part B Does Not Cover

Part B does not cover hospital stays — that is Part A. It does not cover prescription drugs, which require Part D enrollment. Part B also does not cover routine dental care, vision exams for glasses or contacts, hearing aids, or routine foot care (except for people with diabetes or circulatory problems).

Certain services are limited or not covered at all. Routine physical exams are not covered; only the annual wellness visit is free. Cosmetic surgery is not covered unless it is medically necessary after an injury or illness. Long-term care in a nursing home or assisted living is not covered by Part B. If you need these services, you may need to pay out of pocket, use Medicaid if you may have access to, or purchase a separate insurance policy.

Some services require prior approval from Medicare before you receive them. Your doctor's office usually handles this, but it is worth asking whether a procedure needs approval before you schedule it. If you receive a service without approval and Medicare denies it, you could be responsible for the full cost.

How to Find Doctors and Check Coverage

To find doctors who accept Medicare, use the Medicare Provider Search tool at Medicare.gov. You can search by location and specialty. The tool shows whether a doctor accepts Medicare assignment, which means they agree to the standard cost-sharing amounts. Doctors who do not accept assignment can charge more, and you will owe the difference.

Before you schedule a service, ask your doctor's office whether the service is covered by Medicare and whether it requires prior approval. You can also call Medicare directly at 1-800-MEDICARE to ask whether a specific service or procedure is covered. Having this conversation before you receive care helps you avoid surprise bills.

If your doctor recommends a service and you are unsure whether Medicare covers it, ask for the procedure code and call Medicare or your insurance company with that code. This takes a few minutes and can save you hundreds of dollars in unexpected costs.

When to Contact Medicare or Your Doctor

Contact Medicare if you receive a bill you think is wrong, if you are denied coverage for a service you believe should be covered, or if you have questions about whether a service is covered before you receive it. You can reach Medicare at 1-800-MEDICARE, 24 hours a day, seven days a week. You can also create an account at Medicare.gov to view your claims and coverage details online.

Contact your doctor's office if you have questions about whether they accept Medicare assignment, what your out-of-pocket cost will be, or whether a service requires prior approval. Most offices can tell you the cost-sharing amount before your visit.

Seek when ready care if you have chest pain, difficulty breathing, signs of stroke, severe bleeding, or other emergency symptoms. Go to the nearest emergency room or call 911. Emergency care is covered by Part B regardless of whether the hospital is in-network or out-of-network.

Frequently Asked Questions

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

You do not have to, but if you do not enroll during your Initial Enrollment Period and you do not have other may have access to coverage, you will pay a permanent 10 percent penalty on your monthly premium for as long as you have Part B. If you are still working and covered by your employer's health plan, you can delay without penalty, but you must notify Social Security.

What is the difference between the Part B deductible and coinsurance?

The deductible is a set dollar amount you pay each year before Medicare starts to help. Coinsurance is the percentage you pay for each service after you meet the deductible — usually 20 percent. Once you meet the deductible, you pay coinsurance on most services for the rest of the year.

Can I see any doctor I want with Part B?

With Original Medicare, yes — you can see any doctor who accepts Medicare. However, if your doctor does not accept Medicare assignment, they can charge up to 15 percent more than the approved amount, and you will owe that extra cost. With Medicare Advantage, you must use doctors in the plan's network or pay more.

What happens if my doctor does not accept Medicare assignment?

Your doctor can charge up to 15 percent more than what Medicare approves. You would pay your 20 percent coinsurance plus that extra 15 percent. Before scheduling with a doctor who does not accept assignment, ask what the total cost will be so you are not surprised.

Are preventive services really free under Part B?

Yes, preventive services like your annual wellness visit, cancer screenings, vaccines, and certain lab tests are covered at 100 percent with no deductible or coinsurance. However, if your doctor finds a problem during a preventive visit and you need treatment, that treatment is subject to the standard deductible and coinsurance.