Medicare basics • 2026 educational resource

Medicare 101: Parts A, B, C, and D

Medicare is federal health insurance primarily for people 65 or older. Some people qualify earlier because of a disability, End-Stage Renal Disease, or ALS. Understanding the four parts is a useful first step, but the letters do not all describe the same kind of coverage.

Part A: Hospital Insurance

Part A helps cover inpatient hospital care, skilled nursing facility care under qualifying conditions, hospice care, and some home health care. Most people do not pay a monthly Part A premium because they or a spouse paid Medicare taxes long enough while working.

Part B: Medical Insurance

Part B helps cover medically necessary doctors’ services, outpatient care, durable medical equipment, preventive services, and certain drugs administered in medical settings. Part B generally has a monthly premium, an annual deductible, and cost sharing.

Part C: Medicare Advantage

Medicare Advantage is a Medicare-approved private-plan alternative for receiving Part A and Part B coverage. Most plans include Part D drug coverage, and plans may offer additional benefits. Costs, networks, prior-authorization rules, service areas, and benefits vary by plan. You must continue paying the Part B premium.

Part D: Drug coverage

Part D helps pay for covered brand-name and generic drugs. It is offered through private companies approved by Medicare, either as a stand-alone drug plan or commonly within a Medicare Advantage plan. Formularies, pharmacies, premiums, deductibles, and cost sharing vary.

Two main coverage paths

• Original Medicare: Part A and Part B. You may add a separate Part D plan and may be able to purchase Medigap to help with certain out-of-pocket costs.
• Medicare Advantage: A private Medicare-approved plan providing Part A and Part B benefits, usually with Part D included. You cannot use Medigap to pay Medicare Advantage costs.

Questions to answer before comparing coverage

• When do you need to enroll in Part A and Part B?
• Do you have current employer, retiree, union, VA, TRICARE, Medicaid, or other coverage?
• Which doctors, hospitals, pharmacies, and prescriptions matter to you?
• How do premiums, deductibles, copayments, coinsurance, and yearly limits work?
• Will you need coverage while traveling or living in more than one area?

Official sources

• Get started with Medicare
• Medicare coverage options
• 2026 Medicare costs

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Related resources

• Turning 65 Medicare timeline
• Medicare Advantage vs. Medicare Supplement
• Medicare frequently asked questions