Medicare Advantage vs. Original Medicare: What You Need to Know

The Core Difference

Original Medicare is a federal health insurance program run directly by the Centers for Medicare & Medicaid Services (CMS). It covers hospital stays, doctor visits, and some medical equipment through two parts: Part A (hospital insurance) and Part B (medical insurance). You can see any doctor or hospital in the country that accepts Medicare.

Medicare Advantage (also called Part C) is an alternative way to get your Medicare benefits. Private insurance companies run these plans on behalf of Medicare. Instead of going to CMS, you sign up with an insurance company, and that company becomes responsible for providing your Part A and Part B coverage. Most Medicare Advantage plans also include prescription drug coverage (Part D) built in, whereas Original Medicare does not.

The practical difference: with Original Medicare, you hold a card from the federal government and can walk into most hospitals and doctor offices. With Medicare Advantage, you hold a card from a private insurance company, and your coverage depends on which doctors and hospitals are in that company's network.

Key Takeaways

Original Medicare is run by the federal government and lets you see any doctor nationwide who accepts Medicare, while Medicare Advantage is run by private insurance companies and usually limits you to an in-network provider list.
Medicare Advantage plans typically include prescription drug coverage and may offer dental, vision, or hearing benefits that Original Medicare does not cover.
Original Medicare has no annual spending cap, but Medicare Advantage plans have a maximum out-of-pocket limit you cannot exceed in a year.
Original Medicare requires you to buy a separate Medigap policy to cover costs like copays and coinsurance, while Medicare Advantage builds these protections into the plan itself.
You can switch between Original Medicare and Medicare Advantage during the annual enrollment period (October 15 to December 7) or if you have a may have access to life event.

How Networks and Doctor Choice Work

With Original Medicare, there is no network. You can see any doctor, specialist, or hospital in the United States that accepts Medicare. You do not need referrals to see a specialist. This flexibility means you can keep your current doctors even if you move, and you can see out-of-state providers without penalty.

Medicare Advantage plans operate like traditional health insurance with networks. Each plan publishes a list of in-network doctors, hospitals, and specialists. If you see an out-of-network provider, you pay more or the plan may not cover the visit at all. Some plans require you to choose a primary care doctor and get a referral before seeing a specialist. Others (called PPO plans) let you see specialists without a referral but still charge more for out-of-network care.

Before choosing a Medicare Advantage plan, you should check whether your current doctors are in the plan's network. Plans change their networks every year, so a doctor who was covered last year may not be this year.

What Each Plan Covers and What It Costs

Original Medicare covers hospital stays (Part A), doctor visits and outpatient care (Part B), and some preventive services at no cost. It does not cover dental, vision, hearing aids, or prescription drugs unless you buy Part D separately. You pay a monthly premium for Part B, a deductible when you use hospital or doctor services, and then coinsurance (a percentage of the cost) for most services.

Medicare Advantage plans must cover everything Original Medicare covers, but they can charge different amounts. Most plans have lower monthly premiums than Original Medicare plus Medigap, but they have copays and coinsurance for each visit. Many plans include prescription drug coverage, dental cleanings, vision exams, and hearing tests — benefits Original Medicare does not offer. However, these extra benefits vary widely by plan and by region.

The key protection in Medicare Advantage is the annual out-of-pocket maximum. Once you hit that limit (which varies by plan but is capped by federal law), the plan pays 100 percent of your covered costs for the rest of the year. Original Medicare has no such cap, which is why most people on Original Medicare buy a Medigap policy to limit their costs.

Prescription Drug Coverage

Original Medicare does not include prescription drug coverage. If you want it, you must buy a separate Part D plan from a private insurance company. You pay a monthly premium for Part D on top of your Medicare premiums. Part D plans have a deductible, copays for each prescription, and a coverage gap (called the "donut hole") where you pay more out of pocket once you hit a certain spending level.

Most Medicare Advantage plans include Part D coverage built into the plan. You do not buy it separately. The copays and coverage rules are part of your Medicare Advantage plan documents. Some Medicare Advantage plans have no prescription drug coverage, so you would need to buy Part D separately — check the plan details before you enroll.

Medigap Insurance and Out-of-Pocket Costs

Medigap (also called Supplement Insurance) is a policy sold by private insurance companies that works only with Original Medicare. It covers the costs that Original Medicare does not — copays, coinsurance, and deductibles. If you are on Original Medicare and want to limit your out-of-pocket costs, you almost always need a Medigap policy. Medigap premiums vary by age, location, and which plan letter you choose (Plan A, Plan B, Plan G, and so on).

You cannot use Medigap with Medicare Advantage. Medicare Advantage plans are designed to be all-in-one, with the out-of-pocket maximum built in. This means you do not need a separate supplemental policy, but you also cannot buy one if you want to.

When comparing total costs, add up: Original Medicare premiums + Part D premiums + Medigap premiums + out-of-pocket costs. Then compare that to: Medicare Advantage premiums + out-of-pocket costs. The answer depends on your health, which doctors you see, and which medications you take.

When You Can Switch Plans

You can change from Original Medicare to Medicare Advantage, or from Medicare Advantage to Original Medicare, during the Annual Enrollment Period, which runs from October 15 to December 7 each year. Changes take effect January 1. You can also switch if you have a may have access to life event — moving out of your plan's service area, losing other health coverage, getting married or divorced, or becoming may be able to access for Medicaid.

If you are new to Medicare (turning 65 or becoming may be able to access due to disability), you have a seven-month Initial Enrollment Period to choose Original Medicare or Medicare Advantage. If you miss this window and do not have other coverage, you may face a permanent penalty on your premiums.

Once you are enrolled in Medicare Advantage, you can switch to a different Medicare Advantage plan during the Annual Enrollment Period, or you can switch to Original Medicare. If you switch to Original Medicare outside the Annual Enrollment Period, you may have trouble buying a Medigap policy because insurance companies can deny you or charge more based on your health history.

Frequently Asked Questions

Can I see any doctor I want with Medicare Advantage?

Not always. Most Medicare Advantage plans limit you to in-network doctors and hospitals. If you see an out-of-network provider, you pay more or the plan may not cover the visit. Some plans (PPOs) charge more for out-of-network care but still cover it. Check your plan's provider directory before you enroll to make sure your doctors are included.

Do I need Medigap if I have Original Medicare?

You do not need it, but most people on Original Medicare buy it because it protects them from high out-of-pocket costs. Original Medicare has no annual spending cap, so without Medigap you could face very large bills. Medicare Advantage has a built-in out-of-pocket maximum, so you do not need Medigap with that plan.

What happens to my Medicare Advantage coverage if I move?

If you move out of your plan's service area, you can switch to a different Medicare Advantage plan in your new location, or switch to Original Medicare. You have 60 days after you move to make the change. If you stay in the same service area, your coverage continues as is.

Can I have both Original Medicare and Medicare Advantage at the same time?

No. You must choose one or the other. If you enroll in Medicare Advantage, your Original Medicare coverage ends. If you later switch back to Original Medicare, your Medicare Advantage coverage ends.

Does Medicare Advantage cover everything Original Medicare covers?

Medicare Advantage plans must cover all the same services as Original Medicare (hospital, doctor, preventive care), but they can charge different amounts and explore network restrictions. They often add extra benefits like dental or vision, but these vary by plan and region.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.