Medicare Advantage vs Original Medicare: What Is the Difference?

Published by MedicareQuotesForYou. Published July 29, 2026. Last reviewed July 29, 2026.

Short answer

Original Medicare is coverage provided directly by the federal government. It includes Part A (hospital) and Part B (medical), and you can use it with almost any doctor or hospital in the United States that accepts Medicare. It has no network and no annual limit on what you can spend out of pocket, so most people add either a Medigap policy or a Part D drug plan, or both.

Medicare Advantage (Part C) is an alternative offered by private insurance companies approved by Medicare. When you enroll, the plan takes over your Part A and Part B coverage. These plans normally use a provider network, usually include drug coverage, often add dental, vision or hearing benefits, and are required to cap your annual out-of-pocket costs.

Neither option is better for everyone. The choice usually comes down to three things: whether you want freedom to see any Medicare provider, whether your own doctors are in the plan's network, and whether you prefer predictable monthly premiums or lower upfront costs with more variable expenses when you use care.

Side-by-side comparison

Structural differences between the two paths. Dollar amounts for the 2027 plan year are published by CMS in fall 2026; this page is updated when they are released.
Feature	Original Medicare (Parts A & B)	Medicare Advantage (Part C)
Who provides it	The federal government	Private insurers approved by Medicare
Choice of doctors	Almost any provider in the U.S. that accepts Medicare; no referrals needed	Usually a network (HMO or PPO); HMOs often require referrals and going out of network can cost much more
Nationwide coverage	Yes, anywhere in the U.S.	Usually tied to a service area; emergency care is covered away from home
Out-of-pocket maximum	None on its own	Required. Plans must cap annual in-network out-of-pocket costs
Prescription drugs	Not included; you add a separate Part D plan	Usually built in (these are called MA-PD plans)
Dental, vision, hearing	Generally not covered	Frequently included, though the scope of these benefits varies a lot by plan
Monthly premium	You pay the Part B premium, plus any Medigap and Part D premiums	You still pay the Part B premium; many plans add a $0 or low plan premium
Can you add Medigap?	Yes	No. Medigap cannot be used with a Medicare Advantage plan
Prior authorization	Rarely used	Commonly used for higher-cost services
Cost pattern	Higher, more predictable monthly cost; less variation when you need care	Lower upfront cost; more variation depending on how much care you use

Who tends to choose which

Original Medicare, usually with a Medigap policy, tends to suit people who:

Want to see any doctor or specialist that accepts Medicare, without referrals or network restrictions
Travel often, live in more than one state during the year, or spend time away from home
Have a serious or ongoing condition and want the most predictable costs when they use a lot of care
Have specialists or a treatment center they do not want to risk losing
Are willing to pay a higher monthly premium in exchange for that flexibility

Medicare Advantage tends to suit people who:

Want the lowest monthly cost and are comfortable paying copays when they use care
Already use doctors who are in the plan's network
Want drug, dental, vision and hearing benefits bundled into one plan and one card
Stay mostly in one area during the year
Want a hard cap on how much they can spend out of pocket in a year

The detail people most often miss If you start with Medicare Advantage and later want to switch to Original Medicare with a Medigap policy, you may be subject to medical underwriting depending on your state and your timing. In many states an insurer can then decline you or charge more because of your health. Your guaranteed right to buy a Medigap policy is strongest during your Medigap open enrollment period, which normally begins when you are 65 or older and first enrolled in Part B. Because of this, the first choice you make is often easier to make than to reverse. Check the rules in your own state before deciding.

When you can enroll or switch

You cannot change Medicare plans at any time. Changes happen during defined windows:

Annual Enrollment Period (AEP): October 15 to December 7. Anyone with Medicare can join, switch or drop a Medicare Advantage or Part D plan. Changes take effect January 1.
Medicare Advantage Open Enrollment Period: January 1 to March 31. If you are already in a Medicare Advantage plan, you may switch to a different Advantage plan once, or return to Original Medicare and add a Part D plan.
Initial Enrollment Period. A seven-month window around your 65th birthday: the three months before your birthday month, that month, and the three months after.
Special Enrollment Periods. Triggered by qualifying events such as moving out of your plan's service area, losing employer coverage, or your plan leaving your area.

Missing a window usually means waiting until the next one, and in some cases a late enrollment penalty applies for as long as you have coverage. Full guide to Medicare enrollment periods and deadlines.

A note on 2027 figures

The standard Part B premium, deductibles, and the maximum out-of-pocket limits that Medicare Advantage plans are allowed to set are established by the Centers for Medicare & Medicaid Services and change every year. Figures for the 2027 plan year are announced in the fall of 2026. Rather than publish estimates, this page is updated once CMS releases the official numbers, and the review date at the top will change when it is. For current official figures at any time, see Medicare.gov.

Frequently asked questions

Is Medicare Advantage really free?

No. Many Medicare Advantage plans advertise a $0 monthly plan premium, but you still have to pay your Part B premium every month, and you pay copays, coinsurance and deductibles when you use care. A $0 premium describes the plan's own charge, not your total cost of coverage.

Can I have both Medicare Advantage and a Medigap policy?

No. Medigap policies are designed to work only with Original Medicare. It is illegal for someone to sell you a Medigap policy while you are enrolled in a Medicare Advantage plan, unless you are leaving the Advantage plan.

Do I lose Original Medicare if I join a Medicare Advantage plan?

You stay enrolled in Medicare and you keep paying your Part B premium, but your Part A and Part B benefits are administered by the private plan instead of the federal government. You can return to Original Medicare during a valid enrollment period.

What happens if my doctor leaves my plan's network?

Provider networks can change during the year. If your doctor leaves the network, you may pay more to keep seeing them or need to choose another provider. A network change on its own does not always create a Special Enrollment Period, so you may have to wait until the Annual Enrollment Period to switch plans.

Does Original Medicare cover prescription drugs?

Generally no. Part A and Part B cover very few outpatient prescriptions. Most people with Original Medicare add a separate Part D plan. Going without drug coverage when you first become eligible can create a late enrollment penalty that lasts for as long as you have Part D.

Which one is cheaper overall?

It depends on how much care you use. Medicare Advantage usually costs less per month and more when you use services. Original Medicare with a Medigap policy usually costs more per month and less when you use services. Someone who rarely sees a doctor and someone managing a serious condition can reach opposite conclusions from the same two plans.

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