Medicare Parts
at a Glance
Medicare has four main parts: Part A, Part B, Part C, and Part D. Each part covers different types of health care, and understanding how they work together can make Medicare much easier to navigate.
The biggest distinction is this: Original Medicare includes Parts A and B. Medicare Advantage, also called Part C, is an alternative way to receive those benefits. Part D provides prescription drug coverage. You can review Medicare’s official overview of the Parts of Medicare.
Medicare Part A: Hospital Insurance
Medicare Part A mainly helps cover care you receive when you are admitted to a hospital or certain other health care facilities.
Part A generally helps cover:
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Inpatient hospital care
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Skilled nursing facility care when Medicare requirements are met
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Hospice care
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Certain home health care services
Medicare provides more detail about these services in its official Part A coverage overview.
One important thing to remember is that simply spending the night in a hospital does not always mean you are considered an inpatient. Your hospital status can affect whether Medicare Part A or Part B covers your care.
Part A also generally does not cover long-term custodial care, such as ongoing help with bathing, dressing, or eating when skilled medical care is not required.
Medicare Part B: Medical Insurance
Medicare Part B covers many of the medical services you receive outside an inpatient hospital stay.
Part B generally helps cover:
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Doctor and specialist visits
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Outpatient care
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Diagnostic tests
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Durable medical equipment
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Certain home health services
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Preventive screenings and vaccines
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Medicare's Yearly Wellness Visit
You can review Medicare’s official Part B coverage information.
Part B commonly involves deductibles, coinsurance, or copayments. Some preventive services may be available without cost-sharing when Medicare requirements are met.
Certain medications given in a doctor's office or outpatient setting may also be covered under Part B rather than Part D.
Medicare Part C: Medicare Advantage
Medicare Part C, better known as Medicare Advantage, is an alternative to Original Medicare.
Medicare Advantage plans are offered by private insurance companies approved by Medicare. You must generally have both Part A and Part B before joining one. Medicare explains these choices in its guide to Medicare coverage options.
Medicare Advantage (Part C) plans include:
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Part A benefits
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Part B benefits
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Usually Part D prescription drug coverage
Many plans also offer additional benefits that Original Medicare does not routinely cover, such as dental, vision, hearing, or fitness benefits.
Unlike Original Medicare, Medicare Advantage plans may use provider networks and require prior authorization before certain services or medications are covered. Costs and additional benefits vary by plan.
Medicare Part D: Prescription Drug Coverage
Medicare Part D helps pay for prescription medications.
You can generally receive Part D coverage in two ways:
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Add a stand-alone Part D plan to Original Medicare
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Choose a Medicare Advantage plan that includes prescription drug coverage
Medicare provides more information in its official Part D basics guide.
Each Part D plan has a formulary, which is its list of covered medications.
Plans may also have preferred pharmacies and coverage rules such as prior authorization, step therapy, or quantity limits.
Going without Part D or other creditable prescription drug coverage for too long may result in a late enrollment penalty. Medicare explains the rules in its Part D costs and penalty information.
How the Medicare Parts Fit Together
For most people, Medicare coverage follows one of two basic paths.
Original Medicare:
Part A + Part B + optional Part D + optional Medicare Supplement Insurance (Medigap)
Medicare Advantage:
Part C, which includes Parts A and B and usually Part D
Medicare compares these approaches in its overview of Original Medicare and Medicare Advantage coverage options.
What About Medigap?
Medicare Supplement Insurance, or Medigap, is not another part of Medicare.
Medigap works alongside Original Medicare and can help pay some of the deductibles, coinsurance, and copayments left after Medicare pays its share. It generally does not work with Medicare Advantage.
You can learn more from Medicare’s official Medigap coverage guide.
The Bottom Line
An easy way to remember the Medicare parts is:
Part A = Hospital
Part B = Medical
Part C = Medicare Advantage
Part D = Prescription Drugs
Once you understand those four pieces, it becomes much easier to understand the two main ways to receive Medicare coverage: Original Medicare or Medicare Advantage.
Medicare rules and plan benefits can change. For personal coverage questions, review your Medicare or plan documents and visit Medicare.gov.