Lesson 1 of 6
What Is Medicare?
The foundation for everything else in this course — what Medicare is, who qualifies, and how its four parts fit together.
Quick Answer
Medicare is the U.S. federal health insurance program for people 65 and older, and certain younger people with disabilities. It's made up of four parts — A, B, C, and D — that together cover hospital stays, doctor visits, and prescription drugs.
Who Qualifies?
You generally qualify for Medicare at age 65 if you or a spouse worked and paid Medicare taxes for at least 10 years. You can also qualify earlier with 24 months of Social Security Disability Insurance (SSDI), or immediately with End-Stage Renal Disease (ESRD) or ALS. Income has no bearing on basic eligibility — this is one of the biggest differences between Medicare and Medicaid.
The 4 Parts, at a Glance
Part A — Hospital Insurance
Covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health care. Usually premium-free if you have enough work history. We'll go deeper on Part A in Lesson 2.
Part B — Medical Insurance
Covers doctor visits, outpatient care, preventive services, and durable medical equipment. Most people pay a standard monthly premium ($202.90 in 2026).
Part C — Medicare Advantage
A private-plan alternative to Original Medicare, bundling A, B, and often D through an approved insurance company. We'll compare it to Original Medicare fully in Lesson 3.
Part D — Prescription Drug Coverage
Helps cover medication costs, either standalone or bundled into a Medicare Advantage plan. Lesson 4 covers exactly how this works, including the 2026 out-of-pocket cap.
Key term: "Original Medicare" means Parts A and B together, run directly by the federal government. Everything else in this course builds on that foundation.
What Medicare Doesn't Cover
A common misconception is that Medicare covers everything once you turn 65. Original Medicare generally does not cover routine dental, vision, or hearing care, long-term custodial care, or most care outside the U.S. — and it has no annual out-of-pocket maximum. These gaps are exactly why Medicare Advantage plans and Medigap policies exist, which we'll cover in Lessons 3 and 5.
How This Course Is Organized
This lesson gave you the big picture. From here, each lesson goes one level deeper: Lesson 2 covers Part A and Part B in detail, Lesson 3 compares Medicare Advantage to Original Medicare, Lesson 4 explains Part D drug coverage, Lesson 5 covers Medigap supplement plans, and Lesson 6 walks through exactly when and how to enroll. For a broader, single-page version of this material, see our What Is Medicare? guide.
Why Getting This Right Matters
Medicare's structure can feel like alphabet soup at first, but understanding it isn't just academic — it directly affects your wallet and your care. Enrolling late, or in the wrong combination of parts for your situation, can mean permanent late enrollment penalties added to your premium for as long as you have that coverage. Choosing between Medicare Advantage and Original Medicare without understanding the tradeoffs can mean discovering your preferred doctor isn't in-network, or facing unexpectedly high costs in a bad health year.
The goal of this course isn't to make you an expert on Medicare policy — it's to make sure you understand enough to ask the right questions and avoid the most common, most costly mistakes. If you want the short version of what those mistakes look like before working through the full course, see our Top 7 Medicare Mistakes to Avoid guide.
Frequently Asked Questions
What is Medicare?
Medicare is the federal health insurance program for people 65 and older, and certain younger people with disabilities, End-Stage Renal Disease (ESRD), or ALS. It's administered by the Centers for Medicare & Medicaid Services (CMS).
What are the 4 parts of Medicare?
Part A (hospital insurance), Part B (medical insurance), Part C (Medicare Advantage, a private-plan alternative), and Part D (prescription drug coverage). Parts A and B together are called Original Medicare.
Do I need all 4 parts?
Most people need Part A and Part B at minimum. From there, you choose either a Medicare Advantage plan (which often bundles Part D) or a standalone Part D plan alongside Original Medicare. Skipping drug coverage entirely can lead to a lasting penalty.
Is Medicare the same as Medicaid?
No. Medicare is federal and based on age or disability, not income. Medicaid is a joint federal-state program based on financial need. See our full comparison for the complete breakdown.
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