The four parts of Medicare, side by side.
Medicare has four parts, each doing one specific job. Once you see them next to each other, the alphabet finally makes sense.
The table worth printing
| Part | What it is | What it covers | 2026 cost snapshot |
|---|---|---|---|
| Part A | Hospital / Building | Inpatient hospital, skilled nursing, hospice, home health | $0 premium if 40+ quarters worked; $1,736 deductible per benefit period |
| Part B | Medical / People | Doctor visits, outpatient, preventive care, equipment | $202.90/mo premium; $283 deductible; 20% coinsurance after deductible |
| Part C | Private bundle | All of A + B through a private plan; often includes extras | Premiums from $0; includes annual out-of-pocket maximum |
| Part D | Pharmacy | Prescription drug coverage | ~$34.50/mo average premium; $615 max deductible; $2,100 yearly cap |
How the parts combine
The four parts do not all work independently. You combine them in one of two stacks, depending on which road you choose.
Stack 1: Original Medicare path
- Part A (hospital)
- Part B (medical)
- Medigap (fills gaps)
- Part D (drugs)
Stack 2: Medicare Advantage path
- Part A + B (through private plan)
- Part C = the bundle itself
- Often includes Part D
- Often includes extras (dental, vision)
Three confusions this lesson retires
- Part C does not replace Part A. It replaces both A and B. When you are in an Advantage plan, you still have A and B — the plan just delivers those benefits for you.
- Part D is separate from Part C (sometimes). Some Medicare Advantage plans include drug coverage (called MAPD). Stand-alone Part D plans are for people on Original Medicare.
- Medigap is not Part C. Medigap is a private supplement that works alongside Original Medicare. It does not replace Parts A and B — it covers the gaps they leave behind.
Professor's Note: Understanding which parts stack together is the key to making a smart Medicare decision. Once you see the two stacks clearly, every plan brochure, every sales pitch, and every piece of mail from a carrier will make a lot more sense. If it ever does not, call us.
Questions from this lesson
Do I need all four parts?
Almost everyone needs Parts A and B. Part D is optional but recommended (and penalized if skipped). Part C replaces Parts A and B, so you do not use them alongside it. The combination you need depends on whether you choose Original Medicare or Medicare Advantage.
What is the difference between Part C and Original Medicare?
Part C (Medicare Advantage) is a private plan that bundles your Part A and Part B coverage into one plan, often adding extras like dental and vision. Original Medicare keeps A and B as separate government-run coverage, and you can add Medigap and Part D on top.
Can I switch between Original Medicare and Medicare Advantage?
Yes, but only during specific enrollment periods. The Annual Enrollment Period (Oct 15 – Dec 7) and the Medicare Advantage Open Enrollment Period (Jan 1 – Mar 31) allow changes. After your initial enrollment, switching back to Original Medicare may lose Medigap guaranteed-issue rights.
Is Part D really necessary if I take no medications?
Even if you take no drugs now, skipping Part D triggers a permanent late enrollment penalty of 1% per month for every month you were without creditable coverage. This penalty is added to your premium for as long as you have Part D. Enrolling protects you from this lifetime cost.
Want every option compared for you?
We walk through both stacks and show you which one fits your doctors, medications, and budget.