Medicare Part A and Part B Coverage Explained: What’s Included and What’s Not

Understanding what Medicare Part A and Part B cover is one of the most important steps in planning your health care in retirement. These two parts make up what’s often called “Original Medicare”, and together they provide a broad foundation of hospital and medical coverage.

This guide walks you through, in plain language, what each part pays for, what you’re responsible for, and where the gaps are so you can plan ahead with fewer surprises.

Medicare Basics: How Parts A and B Work Together

Original Medicare includes:

• Medicare Part A – Hospital Insurance
• Medicare Part B – Medical Insurance

Most people get both. Part A and Part B work together like this:

• Part A focuses on inpatient care (when you’re formally admitted to a facility).
• Part B focuses on outpatient care (doctor visits, tests, and many services where you are not admitted as an inpatient).

You can use any doctor or hospital that accepts Medicare, and Medicare generally pays a set share of approved services while you pay deductibles, coinsurance, and copayments.

What Does Medicare Part A Cover?

Medicare Part A is often called hospital insurance, but it covers more than just hospital stays.

1. Inpatient Hospital Care

Part A helps cover:

• Semi-private room (shared room)
• Meals
• General nursing care
• Drugs and supplies needed as part of your inpatient treatment
• Services and care provided by the hospital during your stay

Covered settings can include:

• Acute care hospitals
• Critical access hospitals
• Inpatient care in some psychiatric hospitals (with certain limits)

You usually pay:

• A deductible per benefit period (not per year)
• Daily coinsurance if you stay beyond certain day limits

Important: Being in a hospital “under observation” is usually billed as outpatient under Part B, even if you stay overnight. Only a formal inpatient admission falls under Part A.

2. Skilled Nursing Facility (SNF) Care

Part A may cover skilled nursing facility care if you meet specific conditions, such as:

• A qualifying inpatient hospital stay beforehand
• You need skilled nursing or rehabilitation services, not just custodial care (like help with bathing or dressing only)

Covered services in a Medicare-certified SNF generally include:

• Semi-private room
• Meals
• Skilled nursing care
• Physical, occupational, or speech therapy
• Medical social services
• Medications, medical supplies, and equipment used during the stay

You may pay:

• $0 for the first portion of your covered days
• A daily coinsurance for additional days
• All costs beyond the covered day limit

3. Home Health Care (When Covered by Part A)

Medicare can cover certain home health services under Part A or Part B (depending on the situation) when:

• You’re considered homebound by your provider, and
• You need part-time or intermittent skilled nursing care, or therapy services

Covered home health services can include:

• Part-time skilled nursing
• Physical therapy
• Occupational therapy
• Speech-language pathology services
• Medical social services
• Certain medical supplies

Medicare does not cover 24-hour home care, meal delivery, or housekeeping when these are the only services you need.

4. Hospice Care

For people with a terminal illness who choose comfort-focused (palliative) care instead of curative care, Part A can cover hospice if you meet eligibility criteria.

Hospice services may include:

• Doctor and nursing services
• Medications for symptom control and pain relief
• Medical equipment (like wheelchairs or walkers)
• Counseling and social services
• Short-term inpatient respite care for caregivers

You typically pay:

• A small copayment for certain prescription drugs and outpatient respite care
• No deductible for hospice care itself

5. Limited Inpatient Mental Health Care

Part A covers inpatient psychiatric care in:

• General hospitals
• Psychiatric hospitals (with a lifetime limit on covered days in a standalone psychiatric facility)

Services are similar to other inpatient hospital care, including room, meals, and nursing care.

What Does Medicare Part B Cover?

Medicare Part B is your medical insurance for outpatient and professional services. It generally covers services that are medically necessary to diagnose or treat a condition, along with many preventive services.

You usually pay:

• A monthly premium
• An annual deductible
• Coinsurance (often 20% of the Medicare-approved amount) for most covered services, after meeting your deductible

1. Doctor Visits and Professional Services

Part B typically covers:

• Visits to primary care providers
• Visits to specialists (cardiologists, dermatologists, etc.)
• Certain services from nurse practitioners, physician assistants, and other qualified health professionals
• Telehealth visits in many situations

Visits can be for:

• New or existing health issues
• Follow-up care
• Ongoing management of chronic conditions

Medicare usually pays 80% of the approved amount for covered services after you meet your Part B deductible, and you pay the remaining 20% coinsurance, plus any applicable excess charges if allowed in your state.

2. Outpatient Care and Services

Part B covers a wide range of outpatient services, such as:

• Outpatient hospital care (including some surgeries and procedures)
• Emergency room services billed as outpatient care
• Observation services in a hospital
• Outpatient mental health services
• Diagnostic tests and minor procedures performed in a doctor’s office or clinic

You’re generally responsible for your deductible and coinsurance.

3. Preventive Services and Screenings

A key feature of Part B is coverage of many preventive services designed to detect issues early. These may include:

• Welcome to Medicare preventive visit (one-time, when you first enroll in Part B)
• Yearly “Wellness” visits
• Certain vaccinations, such as flu, pneumonia, and others that Medicare covers
• Screenings for conditions like cardiovascular disease, diabetes, certain cancers, and more, when criteria are met
• Counseling for issues like tobacco use in specific situations

Many preventive services are covered at no additional cost to you if your provider accepts Medicare assignment and you meet eligibility criteria for that service.

4. Lab Tests and Imaging

Commonly covered under Part B:

• Blood tests and other lab work ordered by your provider
• X-rays and other radiology services
• Advanced imaging, such as CT scans or MRIs, when medically necessary

Medicare usually covers these at the approved amount, and you may owe a coinsurance share.

5. Durable Medical Equipment (DME)

Part B helps cover durable medical equipment ordered by your provider for use at home, such as:

• Wheelchairs and walkers
• Hospital beds
• Oxygen equipment and supplies
• Certain blood sugar monitors and supplies
• Some types of continuous glucose monitors and related supplies

You generally pay 20% of the Medicare-approved amount if the supplier is enrolled in Medicare and meets program rules.

6. Outpatient Mental Health and Substance Use Services

Part B can cover:

• Individual and group therapy sessions
• Visits with psychiatrists, psychologists, and other mental health professionals who accept Medicare
• Certain substance use treatment services in outpatient settings
• Partial hospitalization programs (intensive outpatient mental health services)

You usually pay coinsurance after your Part B deductible.

7. Certain Outpatient Drugs

Medicare Part B covers some drugs administered in a medical setting, such as:

• Infused or injected medications you receive at a doctor’s office or outpatient clinic
• Certain drugs used with durable medical equipment (for example, a nebulizer)

Most self-administered prescription drugs are not covered by Part B; those typically fall under Medicare Part D (separate prescription drug coverage).

Side-by-Side: What Part A vs. Part B Typically Cover

Use this summary as a quick reference. Coverage always depends on Medicare rules and whether services are medically necessary.

What Medicare Part A and B Do Not Typically Cover

Even with both Medicare Part A and Part B, there are important coverage gaps. People are often surprised by these, so they’re worth calling out clearly.

Original Medicare usually does not cover:

• Routine dental care, such as cleanings, fillings, dentures (except in limited, medically linked situations)
• Routine vision care, such as eyeglass exams, eyeglasses, or contact lenses in most cases
• Routine hearing exams and hearing aids
• Most prescription drugs you take at home (those are usually under Part D or other coverage)
• Long-term custodial care, such as help with bathing, dressing, or eating when that is the only care you need
• 24-hour home care or private-duty nursing (outside specific covered services)
• Cosmetic surgery (with limited exceptions related to accidents or disease)
• Most care received outside the United States, with a few specific exceptions

Knowing these exclusions helps you decide whether you may want additional coverage, such as Medicare Supplement (Medigap) plans, Medicare Part D for prescriptions, or a Medicare Advantage (Part C) plan.

How Costs Work Under Medicare Part A and B

While this guide focuses on what Medicare covers, it’s helpful to understand the basic cost-sharing structure.

Under Part A

Costs generally include:

• Deductible per benefit period for inpatient hospital stays
• Daily coinsurance for longer stays in the hospital or skilled nursing facility
• Potential full costs once you exceed coverage day limits

Many people pay no monthly premium for Part A if they or a spouse worked and paid Medicare taxes long enough. Others may pay a premium if they don’t have enough work history.

Under Part B

Typical costs include:

• A monthly premium (amounts can vary based on income and enrollment timing)
• An annual deductible
• Usually 20% coinsurance for most approved services after the deductible
• Possible additional out-of-pocket amounts if providers do not accept Medicare assignment (depending on state rules)

There is usually no annual out-of-pocket maximum under Original Medicare alone, which is why some people consider supplemental coverage.

When Do Services Fall Under Part A vs. Part B?

Sometimes it’s not obvious whether a service is billed under Part A or Part B. A few guiding points:

• If you are formally admitted to the hospital as an inpatient → Part A
• If you are in the hospital but on observation or only receiving outpatient services → Part B
• If you receive care in a doctor’s office, clinic, or outpatient department → usually Part B
• If you receive home health services → may be Part A or Part B, depending on the situation and whether you had a recent hospital stay
• Emergency room visits that do not lead to an inpatient admission → Part B

When in doubt, asking how your visit is being classified (inpatient vs. outpatient vs. observation) can help you anticipate whether Part A or Part B will apply and what your share of the cost might be.

How Parts A and B Fit With Other Medicare Coverage

To fully understand Medicare coverage, it helps to see where Parts A and B fit within the larger Medicare picture:

• Original Medicare = Part A + Part B
• Part D = Standalone prescription drug coverage that you can add to Original Medicare
• Medigap (Medicare Supplement) = Optional private coverage that helps pay some out-of-pocket costs from Parts A and B (like deductibles and coinsurance)
• Medicare Advantage (Part C) = An alternative way to receive your Medicare benefits through a private plan that bundles Part A and B, and often Part D and extra benefits

Even if you choose a Medicare Advantage plan later, it is built on the core benefits that start with what Medicare Part A and B cover.

Key Takeaways: What Medicare Part A and B Cover ✅

To wrap up, here are the main points to remember:

• Medicare Part A covers:

  • Inpatient hospital stays
  • Skilled nursing facility care (after a qualifying hospital stay)
  • Hospice care
  • Some home health care

• Medicare Part B covers:

  • Doctor and specialist visits
  • Outpatient hospital services and ER care (if not admitted)
  • Preventive services and screenings
  • Lab tests, imaging, and many diagnostic services
  • Durable medical equipment
  • Outpatient mental health care
  • Certain drugs given in a clinic or doctor’s office

• Original Medicare does not usually cover routine dental, vision, and hearing care, most prescription drugs taken at home, or long-term custodial care.

Understanding these basics can help you:

• Anticipate which services are likely to be covered
• Estimate your potential out-of-pocket costs
• Decide whether you need additional coverage beyond Parts A and B

If you are comparing options or deciding when and how to enroll, reviewing your typical health needs and asking specific questions about how your common services are covered can make the next steps clearer and more confident.