Medicare Parts A, B, C, and D Explained

Medicare uses letters for different coverage components, but the letters do not represent four plans that everyone buys together. Parts A and B form Original Medicare. Part C is Medicare Advantage, an alternative way to receive Medicare-covered health benefits. Part D is prescription-drug coverage.

Part A: Hospital Insurance

Medicare.gov explains that Part A helps cover inpatient hospital care, skilled nursing facility care when Medicare conditions are met, hospice, and certain home health care. Enrollment, premiums, benefit periods, deductibles, and eligibility depend on the person’s record and current Medicare rules.

Part B: Medical Insurance

Part B helps cover services from physicians and other providers, outpatient care, durable medical equipment, certain home health services, and many preventive services. Part B generally has a monthly premium and cost sharing; official amounts can change each year.

Part C: Medicare Advantage

Medicare Advantage is offered by private plans approved by Medicare. A member must have Parts A and B and continues paying the Part B premium. Plans provide Part A and Part B benefits and generally include Part D; they may use networks, referrals, prior authorization, and plan-specific costs. Extra benefits, if offered, vary.

Part D: Prescription drug coverage

Part D is offered through Medicare-approved private plans, either as a stand-alone drug plan with Original Medicare or commonly within Medicare Advantage. Each plan has a formulary, pharmacies, tiers, utilization rules, and costs that can change. Checking exact medications is essential.

Two main coverage paths

Original Medicare	Medicare Advantage
Includes Part A and Part B	Alternative way to receive Part A and Part B benefits
May add a stand-alone Part D plan	Usually includes Part D
May add a Medigap policy if eligible	Cannot be combined with Medigap
Broad provider access to those accepting Medicare	Often uses a plan network and plan rules

Medigap is not a Medicare part

Medicare Supplement Insurance, or Medigap, is private coverage designed to help with certain cost sharing in Original Medicare. It is not Part C or Part D and does not work with Medicare Advantage. Eligibility, enrollment rights, underwriting, and standardized plan availability vary by state and timing.

Review the actual documents

Explore medicare services, review the insurance FAQs, or ask for a document-based comparison.

Official sources

• Medicare.gov: Parts of Medicare
• Medicare.gov: Coverage options

Educational notice: American Mutual Insurance Agency LLC is an independent insurance agency and is not connected with or endorsed by the U.S. government or the federal Medicare program. General educational information only. Plan availability, benefits, formularies, networks, costs, and eligibility vary. Verify current information with Medicare.gov, 1-800-MEDICARE, the plan, official documents, and a properly licensed agent.