Medicare Part A covers hospital care. Part B covers medical care. Part C is Medicare Advantage, a private-plan way to receive Part A and Part B benefits. Part D covers prescription drugs. The first big choice is whether to use Original Medicare or a Medicare Advantage plan.

If you are not sure whether these choices apply to you yet, start with our plain-English Medicare eligibility guide.

Medicare Parts at a Glance

  • Part A: Inpatient hospital care, limited skilled nursing facility care, hospice, and some home health care.
  • Part B: Doctor visits, outpatient care, preventive services, medical equipment, and many tests and treatments.
  • Part C: Medicare Advantage, an alternative way to receive Part A and Part B benefits through a Medicare-approved private plan. Most plans also include Part D.
  • Part D: Prescription drug coverage through a private plan that follows Medicare rules.

Think of Parts A and B as the base. You can keep that base as Original Medicare, or receive those benefits through a Medicare Advantage plan under Part C. Drug coverage is then added through Part D or included in many Medicare Advantage plans.

Part A Covers Inpatient and Hospital Care

Medicare Part A is often called hospital insurance. It helps cover inpatient hospital stays, skilled nursing facility care after a qualifying hospital stay, hospice, and some home health care.

Most people qualify for premium-free Part A because they or a spouse paid Medicare taxes long enough while working. Premium-free does not mean cost-free. Part A has a deductible for each benefit period and may charge daily coinsurance for longer stays.

Part B Covers Doctors and Outpatient Care

Medicare Part B covers outpatient services such as doctor visits, preventive care, lab tests, durable medical equipment, and many procedures that do not require an inpatient stay.

Part B has a monthly premium and an annual deductible. After the deductible, you usually pay 20% of the Medicare-approved amount for covered services when the provider accepts assignment. Supplemental coverage may help with that share.

Parts A and B Together Are Original Medicare

Original Medicare lets you use any doctor or hospital in the United States that accepts Medicare. In most cases, you do not need a referral to see a specialist or prior approval for covered services.

Original Medicare does not include routine prescription drug coverage. You can add a separate Part D plan and may be able to buy a Medigap policy to help cover deductibles and coinsurance.

Part C Is Medicare Advantage

Medicare Part C, better known as Medicare Advantage, is an alternative to receiving benefits directly through Original Medicare. You still have Medicare and must keep Part A and Part B. A Medicare-approved private plan manages those benefits instead.

Most Medicare Advantage plans include Part D drug coverage. Plans may also offer dental, vision, hearing, or other benefits that Original Medicare does not cover. The tradeoff is that the plan may use a provider network, require referrals, or require prior authorization for certain care.

See the full Original Medicare vs Medicare Advantage comparison before choosing between the two.

Part D Covers Prescription Drugs

Medicare Part D helps pay for outpatient prescription drugs. You can join a separate Part D plan with Original Medicare, or get drug coverage through most Medicare Advantage plans.

Each plan has its own formulary, pharmacy network, deductible, and cost tiers. Compare plans using your real medication list because the cheapest premium can still produce the larger total bill.

Medigap Works Only With Original Medicare

Medigap is private supplemental insurance that can help pay some costs left by Original Medicare. You cannot use Medigap to pay Medicare Advantage plan costs. That is one reason the Original Medicare versus Medicare Advantage decision comes before choosing supplemental coverage.

Compare the Coverage You Will Actually Use

Start with your doctors, hospitals, prescriptions, travel habits, and budget. Check whether your providers accept Medicare or belong to a plan network. Then compare premiums, deductibles, copays, coinsurance, drug coverage, prior authorization rules, and the yearly out-of-pocket limit.

The official Medicare parts guide and coverage comparison provide the current federal rules. Plan costs and networks can change each year, so confirm the details for the coverage year you are choosing.