Four parts. Two main ways to get your coverage.

Who can qualify?

Medicare generally serves people 65 and older and certain younger people with qualifying disabilities, ALS, or End-Stage Renal Disease. Citizenship or lawful-residence and other eligibility requirements apply. Social Security determines eligibility; an insurance inquiry does not enroll you.

Learn about disability eligibility and Medicare’s 25th-month rule →

Part A: hospital insurance

Part A helps cover eligible inpatient hospital care, skilled nursing facility care, hospice, and certain home health services. It does not generally cover ongoing custodial long-term care.

Most people qualify for premium-free Part A through about 10 years (40 quarters) of Medicare-covered work, on their own or an eligible spouse’s record. Certain disability-related routes also qualify. If you do not qualify for premium-free Part A, you may be able to buy it subject to eligibility rules. Premium-free does not mean every service is free: deductibles, coinsurance, and coverage requirements remain.

Part B: medical insurance

Part B helps cover doctors, outpatient care, preventive services, durable medical equipment, and certain home health services. Most people pay a monthly premium. Under Original Medicare, many services have 20% coinsurance after the annual deductible when the provider accepts assignment; individual services have different rules.

Original Medicare has no annual out-of-pocket limit for Part A and B services. Consider how you would manage cost sharing, including any employer coverage, Medicaid, or eligible supplemental coverage.

Part C: Medicare Advantage

A Medicare Advantage plan is a private-plan alternative for receiving Part A and Part B benefits, usually with Part D included. You need both A and B and must meet the plan’s enrollment and service-area requirements. You generally continue paying your Part B premium, even if the plan advertises a $0 plan premium.

Compare provider networks, drug coverage, copayments, prior authorization, and the annual limit on covered Part A and B out-of-pocket costs. That medical limit does not mean all premiums or prescription expenses count toward it. Extra benefits and costs can change each year. Hospice is generally paid through Original Medicare even if you have Medicare Advantage.

Compare HMO, HMO-POS, PPO, PFFS, SNP and MSA plans →

Part D: prescription drug coverage

Private Medicare-approved plans provide Part D, either through a stand-alone drug plan with Original Medicare or usually within Medicare Advantage. Check your exact medicines, doses, pharmacies, formulary, and restrictions each year. Some drugs are covered under Part B instead. A low premium alone does not tell you the total annual cost.

Where does Medigap fit?

Medicare Supplement Insurance (Medigap) helps with certain Original Medicare cost sharing. It is not Medicare Advantage and cannot be used to pay Medicare Advantage copayments. Modern Medigap policies do not include Part D drug coverage.

Your federal Medigap Open Enrollment Period generally lasts six months starting the first month you are 65 or older and enrolled in Part B. Outside it, medical underwriting may apply unless you have a guaranteed-issue right or broader state protection. Fall Medicare Open Enrollment is not an annual guaranteed right to buy any Medigap policy.

A practical comparison checklist

• Can you see your doctors and use your preferred hospitals?
• What will your prescriptions cost at your pharmacy?
• What could you owe during a difficult medical year?
• Do referrals, networks, or prior approvals affect your care?
• How does travel, moving, or existing employer coverage affect the choice?

Sources: Medicare & You 2026 and 2027, sections 1–5. General education; plan documents and eligibility rules control. Reviewed October 16, 2026.

Read the current official Medicare & You handbook ↗