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The Big Choice: Original Medicare vs. Medicare Advantage

Which path you take will determine how you get your medical care — and how much it costs

Dena Bunis and Kimberly Lankford,

Updated September 08, 2025

AARP

Reviewed by

Xavier Vaughn, MPH

En español

Published July 01, 2020

/ Updated September 08, 2025

Key takeaways

Original Medicare has many parts. Medicare Advantage is all-in-one.
Original Medicare lets you use any doctor. MA is more limited.
Both must provide same care. MA costs differ from original Medicare.
Original Medicare goes anywhere in U.S. MA has geographic limits.
Many states’ Medigap rules make leaving Medicare Advantage hard.

Once you’re signed up for Medicare Parts A and B, you get to choose the type of coverage that best meets your needs — original Medicare or a Medicare Advantage plan.

If you decide on federally run original Medicare, you’ll have several separate pieces that work together:

Part A helps pay for inpatient hospital and skilled nursing care, some home care and end-of-life hospice care.
Part B covers doctors’ services, diagnostic screenings, durable medical equipment, lab tests, outpatient care and preventive services.
A separate Part D plan is available to purchase because original Medicare doesn’t cover prescription drugs that you pick up from pharmacies.
A Medicare supplement policy, better known as Medigap, also can be bought to help with Medicare’s deductibles and copayments.

If you choose a Medicare Advantage plan, a privately issued alternative also known as Part C, you may have Part A, Part B and Part D all in one plan. In 2025, nearly 9 in 10 Medicare Advantage plans included prescription coverage.

If you select a Medicare Advantage plan, you’re not allowed to purchase a Medigap policy. Medicare Advantage plans have different copayments and deductibles than original Medicare.

These all-in-one plans have become increasingly popular. As of May 2025, more than 35 million people — about 51 percent of eligible Medicare beneficiaries — were enrolled in a Medicare Advantage plan.

In 2025, the average beneficiary had 42 Medicare Advantage plans to choose from.

“There are trade-offs in choosing one kind of coverage over the other,” says Meredith Freed, senior policy manager with KFF’s Program on Medicare Policy. KFF, formerly the Kaiser Family Foundation, is a Washington-based nonpartisan health policy nonprofit.

“A Medicare Advantage plan may have zero-dollar premiums, availability of extra benefits, reduced cost sharing for many services and an out-of-pocket spending limit,” Freed says. “Those things are attractive to people, but it also comes with provider networks and prior authorization.”

You’ll use Medicare differently depending on whether you pick original coverage or Medicare Advantage. Here’s a comparison of how each works.

The way you pay for your doctors could change

Original Medicare. You can choose any primary care doctor or specialist who accepts Medicare. You don’t need referrals to see any provider, and you don’t have to worry about your doctor leaving a plan’s network.

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Only 1 percent of doctors who treat adults don’t participate in Medicare, according to KFF. So chances are good your current doctor accepts Medicare and you won’t have to change providers.

But be aware: If you’re looking for a new doctor, about 1 in 6 primary care physicians won’t take new patients in general. That’s something to note if you plan to move or your doctor is retiring.

Medicare Advantage. Similar to employer coverage with provider networks that limit you to their doctors, the plans may not pay for out-of-network services. So your costs will increase if you use a doctor not in the network.

Often, you’ll have a primary care physician directing your care, but many Medicare Advantage enrollees need a referral to see a specialist. Make sure the doctors you want to see are in the plan’s network.

Both types cover basics but vary on some ‘extras’

By law, original Medicare and Medicare Advantage plans both must provide coverage for the same medical services, including blood work; diagnostic tests, such as X-rays and other scans; doctor visits; hospitalizations; and outpatient surgery.

Original Medicare. Original Medicare won’t pay for routine dental, hearing, and vision care.

Medicare Advantage. You can expect prior authorization requirements. Most Advantage plans provide some dental, hearing and vision care. Some even extend coverage to gym memberships, over-the-counter medications and transportation to the doctor’s office. Original Medicare doesn’t cover these types of supplemental benefits.

What you’ll pay with original Medicare, Medicare Advantage

Even though original Medicare and Medicare Advantage must cover the same Part A and Part B services, you may have different out-of-pocket costs.

Original Medicare. The federal government sets Medicare premiums, deductibles and coinsurance amounts for Part A and Part B. For example, you’re responsible for 20 percent of a doctor visit or lab test bill under Part B.

Most people don’t pay a premium for Part A because they or their spouse paid Medicare taxes for at least 10 years. But they do pay Part B premiums, which are $185 a month for most people in 2025; high earners pay more.

Often, those with original Medicare also purchase a supplemental Medigap policy to help defray out-of-pocket costs. While original Medicare doesn’t have an annual cap on out-of-pocket costs, a Medigap policy may pay for most of your deductibles and copayments.

AARP Audio · Does Medigap Cover Preexisting Conditions?

Medicare Advantage. You’ll still pay the government-set annual Part B premium and the Part A premium, if required. Sometimes you’ll pay an additional premium for the Medicare Advantage plan although about two-thirds of Medicare Advantage enrollees in 2025 are in plans with no additional premiums.

But instead of paying the 20 percent coinsurance for doctor visits and other Part B services, most Medicare Advantage plans have set copay amounts for a physician visit, such as $20 or $50.

Medicare Advantage plans have an annual cap on out-of-pocket expenses: In 2025, it’s $9,350 for in-network services and $14,000 total for in-network and out-of-network services. Some plans have lower maximums.

Where you live and travel matters

Original Medicare. You can access care anywhere in the United States as long as the provider accepts Medicare.

Medicare Advantage. Plans are based around provider networks usually limited to specific geographic areas.

So if you travel a lot or have a vacation home where you spend time, your care may not be covered if you go to an out-of-network provider — or you’ll pay more for care. Emergency and some urgent care are covered if you’re traveling within the U.S.

While Medicare Advantage plans are available pretty much throughout the U.S., the choice of plans is more limited in rural areas.

Neither original Medicare nor Medicare Advantage pays for your health care abroad.

Why switching back and forth is difficult

You aren’t locked into the choice between original Medicare and Medicare Advantage that you will make when you first enroll in Medicare, and going from original Medicare to Medicare Advantage is easy. You have an opportunity every year during Medicare’s open enrollment season, Oct. 15 to Dec. 7.

However, switching from Medicare Advantage to original Medicare can be trickier.

The reason? Medigap. When you first enroll in Medicare, either in your seven-month initial enrollment period or a six-month Medigap open enrollment period that starts the first month you’re 65 and have Medicare Part B, you can buy any Medigap policy available in your state, no matter your health, and it likely will be cheaper than you’ll ever find later.

Medigap open enrollment is a once-in-a-lifetime opportunity that you have when you choose original Medicare. If you decide to switch to original Medicare later, insurers can reject you because of preexisting conditions, charge you more and delay your coverage after you’re accepted.

Only three states — Connecticut, Massachusetts and New York — allow you to buy any Medigap policy at any time even if you have debilitating illnesses. Minnesota had planned to join the trio in August 2025 but is waiting to start its law until August 2026.

Maine mandates each of its Medigap insurers to choose one month a year when anyone who applies must be accepted into Plan A, a type of policy that offers about half the features of the country’s most popular option available now, Plan G. In 2023, about 1 percent of Medigap enrollees chose Plan A while about a third had Plan G, according to the insurance trade association AHIP, formerly known as America’s Health Insurance Plans.

If you aren’t accepted into a Medigap plan, you face no limit on medical expenses you could owe. With a Medicare Advantage plan, the most you would pay out of pocket in 2025 is $9,350 using in-network services and $14,000 for a combination of in- and out-of-network services.

This story, originally published July 1, 2020, has been updated to reflect the most current information and add a section about the difficulties of buying a Medigap policy after you’re first eligible.

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About the authors

Dena Bunis covered Medicare, health care, health policy and Congress. She also wrote the Medicare Made Easy column for the AARP Bulletin. An award-winning journalist, Bunis spent decades working for metropolitan daily newspapers, including as Washington bureau chief for the Orange County Register and as a health policy and workplace writer for Newsday.

Kimberly Lankford is a contributing writer who covers Medicare and personal finance. She wrote about insurance, Medicare, retirement and taxes for more than 20 years at Kiplinger’s Personal Finance and has written for The Washington Post and Boston Globe. She received the personal finance Best in Business award from the Society of American Business Editors and Writers and the New York State Society of CPAs’ excellence in financial journalism award for her guide to Medicare.

About the reviewer

Xavier Vaughn, an AARP adviser for Medicare programs, previously worked at the National Council on Aging in Arlington, Virginia, and the Primaris Foundation, based in Columbia, Missouri. He earned his master’s degree in public health from the University of Alabama at Birmingham.