Updated July 2026 · Reviewed by the CoverageCo team
Part A covers you as an inpatient, Part B covers you as an outpatient, Part C (Medicare Advantage) is a private way to receive A and B together, and Part D covers prescriptions from a pharmacy. Everything else in Medicare is a variation on how you combine those four.
Key takeaways
- Most people pay no premium for Part A, but nearly everyone pays a monthly Part B premium.
- Part C isn't extra coverage — it's a different way to receive the coverage you already have.
- Part D plans differ enormously by formulary. Comparing on premium alone is the costliest common mistake.
- Original Medicare generally doesn't cover routine dental, vision, hearing, or long-term custodial care.
The short version
Part A covers you as an inpatient. Part B covers you as an outpatient. Part C is a private way to receive A and B together. Part D covers prescriptions you pick up at a pharmacy.
Everything else in Medicare is a variation on how you combine those four.
| Part | What it covers | Typical premium |
|---|---|---|
| Part A | Inpatient hospital, skilled nursing after a qualifying stay, hospice, some home health | Usually $0 with enough work history |
| Part B | Doctor visits, outpatient care, preventive services, lab work, equipment | Monthly premium nearly everyone pays |
| Part C | A private plan delivering Part A + B, usually with Part D and extras | Varies; you still pay your Part B premium |
| Part D | Prescription drugs filled at a pharmacy | Varies widely by plan and formulary |
Part A — hospital insurance
Part A covers inpatient hospital stays, skilled nursing facility care after a qualifying stay, some home health care, and hospice.
Most people pay no premium for Part A, because they or a spouse paid Medicare taxes long enough while working. That's why it's often described as free, though it still has deductibles and coinsurance when you use it.
A common misunderstanding: Part A is not long-term care. It covers short-term skilled nursing after a hospital stay, not ongoing custodial care like help with bathing or dressing. That gap surprises families at the worst possible moment.
Part B — medical insurance
Part B covers doctor visits, outpatient care, preventive services, lab work, durable medical equipment, and much of what happens outside a hospital admission.
Part B has a monthly premium that nearly everyone pays, and higher earners pay more through an income-related adjustment based on a prior year's tax return. If your income has dropped since then — retirement being the obvious case — you can ask Social Security to reconsider using your current situation.
Part C — Medicare Advantage
Part C isn't extra coverage bolted on top. It's a different delivery system. A private insurer approved by Medicare provides your Part A and Part B benefits, usually bundles in Part D, and often adds extras like dental or vision.
In exchange, you generally use a network and may need prior authorization for certain services. You keep paying your Part B premium while on an Advantage plan.
Part D — prescription drug coverage
Part D covers retail prescriptions, through either a standalone drug plan alongside Original Medicare or drug coverage built into a Medicare Advantage plan.
Every Part D plan has a formulary — its own list of covered drugs and what tier each falls on. Two plans with similar premiums can differ enormously for the exact medications you take. This is why comparing drug plans on premium alone is the most common and most expensive Medicare mistake.
Formularies change every year. So does the right plan for you.
How people actually put it together
Almost everyone lands on one of two paths:
- Original Medicare (A and B) + a Medigap policy + a standalone Part D plan. Higher monthly cost, very predictable, no networks.
- A Medicare Advantage plan (C) that bundles A, B, and usually D into one plan. Lower monthly cost, network-based, more variable when you use care.
What Medicare doesn't cover
Worth knowing before you assume you're covered: Original Medicare generally doesn't cover routine dental, routine vision or eyeglasses, hearing aids, or long-term custodial care. Some Advantage plans include limited versions of the first three.
If those matter to you, they should be part of the plan conversation from the start rather than a discovery later.
Common questions
Is Part A really free?
Most people pay no monthly premium for Part A because of their work history, but it isn't free to use. Part A has its own deductible and coinsurance amounts when you're admitted to a hospital or skilled nursing facility.
Do I need Part D if I don't take any prescriptions?
It's still usually worth considering. Going without creditable drug coverage can trigger a Part D late enrollment penalty that's added to your premium permanently once you do enroll — and prescription needs tend to arrive without warning.
Does Medicare cover dental and vision?
Original Medicare generally doesn't cover routine dental or vision care. Some Medicare Advantage plans include limited dental, vision, and hearing benefits, though these are typically capped annually.
Does Medicare cover long-term care?
Not custodial long-term care. Medicare may cover short-term skilled nursing care following a qualifying hospital stay, but not ongoing help with daily activities like bathing or dressing.