The four parts of Medicare
Part A — Hospital Insurance
Helps cover inpatient hospital care, skilled nursing facility care under Medicare rules, hospice, and certain home health services.
Part B — Medical Insurance
Helps cover physician services, outpatient care, preventive services, durable medical equipment, and other medically necessary services.
Part C — Medicare Advantage
An alternative way to receive Part A and Part B benefits through a Medicare-approved private plan. Most Medicare Advantage plans include Part D drug coverage and some offer extra benefits.
Part D — Prescription Drug Coverage
Optional Medicare drug coverage offered by private insurers. It can be a stand-alone plan with Original Medicare or included in many Medicare Advantage plans.
The two main ways to receive Medicare coverage
Path 1: Original Medicare
Original Medicare includes Part A and Part B. You may add a separate Part D prescription drug plan and, if eligible, a Medicare Supplement (Medigap) policy to help with some of the out-of-pocket costs left by Original Medicare.
- You can generally use any doctor or hospital that takes Medicare anywhere in the United States.
- Original Medicare itself does not have a yearly out-of-pocket maximum for Part A and Part B services.
- A Medigap policy can help pay certain deductibles, copayments, and coinsurance, depending on the standardized plan.
- Prescription drug coverage is typically obtained separately through Part D.
Path 2: Medicare Advantage
Medicare Advantage (Part C) replaces Original Medicare as the way you receive your Part A and Part B benefits while you are enrolled in the plan. You remain in Medicare and must keep Part B.
- Plans may use provider networks and service areas.
- Prior authorization or referrals may apply for certain services.
- Most plans include Part D prescription drug coverage.
- Plans may offer additional benefits not covered by Original Medicare.
- Medicare Advantage plans have a yearly maximum out-of-pocket (MOOP) limit on what you pay for covered Part A and Part B services. After you reach that limit, you pay nothing for covered Part A and Part B services for the rest of the calendar year.
Questions worth comparing before choosing
- Are your doctors, hospitals, and specialists available under the option you are considering?
- Do you travel frequently or spend part of the year in another state?
- Which prescription drugs do you take, and are they on the plan formulary?
- What premiums, deductibles, copayments, and coinsurance could apply?
- Would you rather pay a higher predictable monthly premium for supplemental coverage or accept more pay-as-you-use cost sharing?
- Could prior authorization or network rules affect how you receive care?
- If you change your mind later, will you have a guaranteed right to buy Medigap, or could medical underwriting apply?
Compare the two paths
See Medigap/Original Medicare and Medicare Advantage side by side.
When can I enroll or change?
Understand IEP, AEP, MA OEP, Medigap enrollment and Special Enrollment Periods.
Part D details
Learn how formularies, pharmacies and creditable drug coverage affect your choice.
Official Medicare resources
Medicare rules can change. These pages were written from current Medicare.gov guidance and should be reviewed periodically.