What is Medicare Part A?

Medicare Part A is hospital insurance. It helps cover inpatient hospital stays, skilled nursing facility care, hospice, and some home health care. Most people pay no monthly premium for Part A because they (or a spouse) paid Medicare taxes while working for at least 10 years.

What is Medicare Part B?

Medicare Part B is medical insurance. It covers doctor visits, outpatient care, preventive services, lab tests, durable medical equipment, and many other outpatient services. Part B has a standard monthly premium set each year by the federal government.

What is Medicare Part C (Medicare Advantage)?

Medicare Part C, also called Medicare Advantage, is an all-in-one alternative to Original Medicare offered by private insurance companies approved by Medicare. Part C plans must cover everything Part A and Part B cover, and most also include prescription drug coverage (Part D), plus extras like dental, vision, hearing, and fitness benefits.

What is Medicare Part D?

Medicare Part D is prescription drug coverage offered through private insurers. You can add a standalone Part D plan to Original Medicare, or get drug coverage bundled into a Medicare Advantage (Part C) plan. Each plan has its own list of covered drugs (formulary) and pharmacy network.

Do I need all four parts of Medicare?

Most people are automatically enrolled in Part A when they turn 65. From there you choose: keep Original Medicare (Parts A and B) and optionally add a Part D drug plan and a Medigap supplement, OR enroll in a Medicare Advantage plan (Part C) that often bundles A, B, and D together. A licensed agent can help you compare based on your doctors, prescriptions, and budget.

Medicare basics

Medicare Parts Explained: A, B, C & D

Medicare is split into four parts. Each one covers a different type of care. Here is a plain-English guide to what each part is, what it costs, and how the pieces fit together — so you can pick the combination that's right for you.

Medicare Part A — Hospital Insurance

Inpatient care: hospitals, skilled nursing, hospice, and some home health.

Part A is the foundation of Medicare. It helps pay for care you receive while admitted to a hospital, in a skilled nursing facility after a qualifying hospital stay, in hospice, and certain home health services.

Premium: $0 for most people (if you or your spouse paid Medicare taxes for at least 10 years).
Deductible: Per benefit period, set annually by Medicare.
Coinsurance: Kicks in for longer hospital and skilled nursing stays.

You're typically auto-enrolled in Part A at 65 if you're already receiving Social Security benefits.

Medicare Part B — Medical Insurance

Doctor visits, outpatient care, preventive services, lab work, and equipment.

Part B covers the care you receive outside of a hospital stay: visits to your primary doctor and specialists, annual wellness exams, vaccines, lab tests, mental health services, durable medical equipment (like walkers or CPAP machines), and many outpatient procedures.

Premium: Standard monthly premium set each year (higher for high-income beneficiaries).
Deductible: Annual; after that you typically pay 20% of the Medicare-approved amount.
No cap: Original Medicare has no out-of-pocket maximum, which is why many people add a Medigap supplement or choose a Medicare Advantage plan.

Medicare Part C — Medicare Advantage

An all-in-one alternative to Original Medicare from private insurers.

Medicare Advantage (Part C) plans are offered by private insurance companies approved by Medicare. They must cover everything Part A and Part B cover, and most also include Part D prescription drug coverage. Many plans bundle extras like dental, vision, hearing, fitness memberships, and over-the-counter allowances.

Premium: Many plans have a $0 monthly premium (you still pay your Part B premium).
Out-of-pocket max: Required by law, which protects you from unlimited costs.
Networks: HMO and PPO plans use provider networks — check that your doctors and hospitals are in-network.

You can switch between Original Medicare and Medicare Advantage during the Annual Enrollment Period (October 15 – December 7) each year.

Medicare Part D — Prescription Drug Coverage

Standalone drug plans or bundled into a Medicare Advantage plan.

Part D helps pay for prescription medications. You can add a standalone Part D plan to Original Medicare, or get drug coverage built into a Medicare Advantage plan. Every plan has its own formulary (the list of drugs it covers) and preferred pharmacy network, so the right plan depends on the specific prescriptions you take.

Premium: Varies by plan; higher for high-income beneficiaries.
Formulary tiers: Drugs are grouped into tiers that determine your copay.
Late-enrollment penalty: If you go without creditable drug coverage after first becoming eligible, you may pay a permanent monthly penalty.

How the parts fit together

Most people choose one of two paths:

Path 1

Original Medicare

Part A + Part B, usually paired with a standalone Part D drug plan and often a Medigap (Medicare Supplement) policy to help cover the 20% Part B leaves behind.

Path 2

Medicare Advantage

Part C plan that bundles A, B, and usually D together — often with extra benefits and a built-in out-of-pocket maximum.

Frequently asked questions

What is Medicare Part A?: Medicare Part A is hospital insurance. It helps cover inpatient hospital stays, skilled nursing facility care, hospice, and some home health care. Most people pay no monthly premium for Part A because they (or a spouse) paid Medicare taxes while working for at least 10 years.
What is Medicare Part B?: Medicare Part B is medical insurance. It covers doctor visits, outpatient care, preventive services, lab tests, durable medical equipment, and many other outpatient services. Part B has a standard monthly premium set each year by the federal government.
What is Medicare Part C (Medicare Advantage)?: Medicare Part C, also called Medicare Advantage, is an all-in-one alternative to Original Medicare offered by private insurance companies approved by Medicare. Part C plans must cover everything Part A and Part B cover, and most also include prescription drug coverage (Part D), plus extras like dental, vision, hearing, and fitness benefits.
What is Medicare Part D?: Medicare Part D is prescription drug coverage offered through private insurers. You can add a standalone Part D plan to Original Medicare, or get drug coverage bundled into a Medicare Advantage (Part C) plan. Each plan has its own list of covered drugs (formulary) and pharmacy network.
Do I need all four parts of Medicare?: Most people are automatically enrolled in Part A when they turn 65. From there you choose: keep Original Medicare (Parts A and B) and optionally add a Part D drug plan and a Medigap supplement, OR enroll in a Medicare Advantage plan (Part C) that often bundles A, B, and D together. A licensed agent can help you compare based on your doctors, prescriptions, and budget.

Still not sure which path is right for you?

Watch our free 27-minute Medicare 101 replay. We walk through real plan comparisons and the questions to ask before you enroll — no pressure, no sales pitch.

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This guide is for educational purposes only and is not affiliated with or endorsed by the federal Medicare program. Premiums, deductibles, and coverage details are set by Medicare and can change each year. For official information, visit Medicare.gov.