Original Medicare vs. Medicare Advantage: key differences

Updated 2026-10-21 · Reviewed for accuracy by the EKO Labs team. Educational only; not medical advice.

Once you have Medicare Part A and Part B, you choose how to get your coverage: Original Medicare or a Medicare Advantage Plan (Part C). Neither is right for everyone. This guide follows the side-by-side comparison on Medicare.gov so you can see the main differences in doctor choice, costs, drug coverage and extra benefits, and when you are allowed to switch. It is general information, not legal, financial or medical advice.

The two ways to get Medicare

• Original Medicare includes Part A (Hospital Insurance) and Part B (Medical Insurance). You pay for services as you get them: Medicare pays part of the cost and you pay your share. You can add a separate Medicare drug plan (Part D), and you can add supplemental coverage such as Medicare Supplement Insurance (Medigap), coverage from a former employer or union, or Medicaid.
• Medicare Advantage (Part C) is a Medicare-approved plan from a private company that offers an alternative to Original Medicare. It includes Part A and Part B, most plans include Part D drug coverage, and most plans offer extra benefits that Original Medicare does not, like vision, hearing and dental. You must have both Part A and Part B to join one.

Side-by-side: what Medicare.gov says

Doctor and hospital choice

• Original Medicare: you can use any doctor or hospital that takes Medicare, anywhere in the U.S. You may pay more if your doctor does not accept assignment. In most cases you do not need a referral to see a specialist.
• Medicare Advantage: you may need to use doctors and other providers in the plan’s network and service area for non-emergency care. Some plans cover non-emergency care out of network, but it may cost more. You may need a referral to see a specialist.

Costs

• Original Medicare: for Part B-covered services you usually pay 20% of the Medicare-approved amount after you meet your deductible (your coinsurance). You pay a monthly Part B premium, plus a separate Part D premium if you join a drug plan. There is no yearly limit on what you pay out of pocket unless you have supplemental coverage (like Medigap) or other insurance (like Medicaid, or employer, retiree or union coverage).
• Medicare Advantage: you pay the monthly Part B premium and may also pay the plan’s premium. Some plans have a $0 premium, and some help pay all or part of your Part B premium. Out-of-pocket costs vary by plan and by service. Plans have a yearly limit on what you pay for covered Medicare services (which may be different for in-network and out-of-network services); once you reach it, you pay nothing for covered services for the rest of the year. Each year plans set their premiums, deductibles and service costs, and what you pay the plan can only change once a year, on January 1.
• Medigap: you can buy Medigap to help with your out-of-pocket costs in Original Medicare, but you cannot buy Medigap to cover your costs in a Medicare Advantage Plan.

Coverage and approvals

• Original Medicare covers most medically necessary services and supplies in hospitals, doctors’ offices and other health care facilities. It does not cover some things, like routine physical exams, eye exams and most dental care. In most cases you do not need prior authorization.
• Medicare Advantage plans must cover all medically necessary services that Original Medicare covers, and may offer extra benefits such as some vision, hearing and dental services. You may need approval (prior authorization) from the plan before it covers certain services or supplies.

Prescription drug coverage

• Original Medicare: you can join a separate Medicare drug plan (Part D). It is optional and available to everyone with Medicare.
• Medicare Advantage: most plans include Part D, so you do not need a separate drug plan. In most types of Medicare Advantage Plans you cannot join a separate drug plan.
• Every drug plan has a list of covered drugs (a formulary) divided into tiers, and costs differ plan to plan. If you do not join a drug plan when you first get Medicare and go 63 days or more without creditable drug coverage, you may pay a Part D late enrollment penalty. See our guides on formularies and tiers and on Part D and Open Enrollment.

Coverage outside the U.S.

Original Medicare generally does not cover medical care outside the U.S.; some Medigap policies cover emergency care abroad. Medicare Advantage plans generally do not either, although some offer an extra benefit for emergency and urgently needed services when you travel outside the U.S.

When you can join, switch or drop a plan

You can only join, switch or drop a Medicare Advantage Plan or drug plan at certain times, called enrollment periods. Medicare.gov lists these:

• Initial Enrollment Period: generally when you turn 65. It lasts 7 months (3 months before the month you turn 65 through 3 months after). You need both Part A and Part B to join a Medicare Advantage Plan, and either Part A or Part B to join a drug plan. If you join a Medicare Advantage Plan during this period, you can switch to another one or go back to Original Medicare within the first 3 months you have Part A and Part B.
• Open Enrollment Period, October 15 to December 7 every year: you can join, drop or switch Medicare Advantage Plans (with or without drug coverage), switch between Original Medicare and Medicare Advantage, and join, drop or switch a drug plan if you are in Original Medicare. Coverage starts January 1 of the next year, and the plan must get your request by December 7.
• Medicare Advantage Open Enrollment Period, January 1 to March 31: only if you are already in a Medicare Advantage Plan. You can switch to another Medicare Advantage Plan or drop it and return to Original Medicare (and join a separate drug plan).
• Special Enrollment Period: only for certain situations, like moving to a new address, losing or changing your coverage, getting Medicaid or getting Extra Help.

Questions to ask before you choose

• Are my doctors, hospitals and pharmacies in the plan’s network, and is the plan available where I live (including where I spend part of the year)?
• Are my regular prescriptions on the plan’s formulary, and what tier are they in?
• Which services need prior authorization or a referral?
• What is the plan’s yearly out-of-pocket limit, and what are its premium, deductible and copayments?
• Which extra benefits do I actually use (vision, hearing, dental), and what do they cost?
• If I stay in Original Medicare, do I want a Medigap policy, and when does my Medigap enrollment window end? See our Medigap guide.

Where to get free help

Compare plans in your area at Medicare.gov/plan-compare (add the prescription drugs you take regularly for the most accurate cost estimate), or call 1-800-MEDICARE (1-800-633-4227, TTY 1-877-486-2048). Your State Health Insurance Assistance Program (SHIP) gives free, personalized health insurance counseling and is not connected to any insurance company or health plan. Our step-by-step enrollment guide shows how to join a plan.

Sources: Medicare.gov, “Your coverage options,” “Compare Original Medicare & Medicare Advantage,” “Understanding health plan costs” and “Joining a plan.” Checked October 2026. This guide is general information, not legal, financial or medical advice.