The short answer
People with Medicare choose between two ways to get coverage. Original Medicare, Parts A and B, is run by the federal government: you can see any doctor or hospital in the country that accepts Medicare, usually without prior approval, but after the deductibles you pay 20 percent of most costs with no yearly limit, and drug coverage is a separate Part D plan. Many people add a Medigap policy to fill those gaps. Medicare Advantage, or Part C, is a private plan that covers the same services, usually includes drug coverage and extras such as dental or vision, and caps your yearly out-of-pocket costs, at no more than $9,250 in network in 2026, but uses networks and often requires prior authorization. You still pay the Part B premium, $202.90 a month in 2026, with either choice. You can switch each year from October 15 to December 7, but buying a Medigap policy later can be difficult.
Why this matters
This choice decides which doctors you can see, how much you pay when you are sick, and how easy it is to change your mind later. The trade-off is real: Medicare Advantage is often cheaper month to month and limits your worst-case costs, while Original Medicare with a supplement offers the widest choice of providers and the most predictable bills, at a higher premium. Advertising rarely explains the catch on either side. This guide compares the two on networks, costs, drug coverage and switching rules. For how Medicare works overall, start with our guide to Medicare and Medicaid.
How does Original Medicare work?
Original Medicare is Part A, hospital insurance, and Part B, medical insurance, run by the federal government. You can use any doctor, hospital or other provider in the United States that accepts Medicare, and most services need no approval in advance. That coverage works the same anywhere in the country, which matters if you split the year between two homes.
In 2026 you pay a $1,736 deductible for each hospital benefit period under Part A, and under Part B a $283 deductible and then usually 20 percent of the approved amount. There is no yearly cap on what you can pay. Drug coverage comes from a separate stand-alone Part D plan; our guide to Medicare Part D explains it.
Many people buy a Medigap policy from a private insurer to pay most of the deductibles and coinsurance Original Medicare leaves. Medigap plans are standardized by letter, so a Plan G covers the same benefits whichever company sells it, though prices differ. Medigap works only with Original Medicare.
How does Medicare Advantage work?
A Medicare Advantage plan is offered by a private company approved by Medicare. It must cover everything Original Medicare covers except hospice, which Original Medicare continues to pay for. Most plans include Part D drug coverage, and many add benefits Original Medicare does not, such as routine dental, vision and hearing care or fitness programs.
- HMOs generally require you to use the plan's network and to get referrals to see specialists.
- PPOs let you go out of network at a higher cost.
- Special Needs Plans serve people with both Medicare and Medicaid, certain chronic conditions, or who live in a nursing home.
Most plans use networks and require prior authorization for some services, such as hospital stays, imaging or skilled nursing. You still pay the Part B premium, plus any premium the plan charges; many plans charge none, and a few reduce your Part B premium. Medicare rates plans from one to five stars each year on quality and service, and you can switch into a five-star plan in your area once during most of the year.
How do the costs compare?
The two routes spread costs differently:
- Original Medicare alone: Part B premium of $202.90 a month, the deductibles, 20 percent coinsurance with no yearly limit, and a separate Part D premium.
- Original Medicare with Medigap: add the Medigap premium, which varies by plan, age and state, in exchange for low and predictable costs when you use care.
- Medicare Advantage: Part B premium, the plan's premium if any, and copays for each service, up to a yearly out-of-pocket limit of no more than $9,250 in network, or $13,900 in and out of network combined, in 2026. Plans may set lower limits. Part D drug costs, capped separately at $2,100, do not count toward it.
Want to see what this could mean for your situation? Estimate your Medicare premium with our free calculator, including any income-related amount, which applies to both routes.
Worked examples
Example (hypothetical): a healthy new retiree
Carlos is 65, healthy, takes two generic drugs and sees one doctor in his town, who is in a local HMO's network. He chooses a Medicare Advantage plan with no premium beyond Part B and drug coverage included. His monthly cost is low, and in a bad year he would pay at most the plan's out-of-pocket limit, but he needs referrals and must stay in network.
Example (hypothetical): a retiree who travels
Joan has a heart condition, sees specialists at a hospital in another state and spends winters away from home. She chooses Original Medicare with a Medigap Plan G and a Part D plan. Her premiums are higher, but any provider that accepts Medicare will see her without a referral, and after the Part B deductible her Medigap plan pays her remaining share of covered costs.
When can you switch?
- Annual Enrollment Period, October 15 to December 7: move between Original Medicare and Medicare Advantage, change plans, or add or change a Part D plan, with changes starting January 1.
- Medicare Advantage Open Enrollment Period, January 1 to March 31: if you are in a Medicare Advantage plan, switch to another or return to Original Medicare, once.
- Special enrollment periods: after events such as moving out of your plan's area, losing other coverage, or qualifying for Medicaid or Extra Help.
Switching back to Original Medicare is always possible during these windows, but buying Medigap afterwards may not be. After your first six-month Medigap open enrollment period, insurers in most states can ask health questions and refuse you or charge more. There are protections: if you join Medicare Advantage when you first get Medicare and leave within 12 months, or drop a Medigap policy to try Medicare Advantage for the first time and leave within 12 months, you have a right to buy Medigap. A few states give broader rights.
Special situations
If you have Medicare and Medicaid
Full Medicaid usually covers most of Original Medicare's cost-sharing, so a supplement is rarely needed. Dual Eligible Special Needs Plans are Medicare Advantage plans designed to coordinate the two programs; they can be useful, but check the network as carefully as with any plan.
If you have retiree or union coverage
Some former employers provide coverage through their own Medicare Advantage plan or require you to keep Original Medicare. Joining a different plan on your own can end your retiree benefits, sometimes for good, and may end coverage for a spouse too. Ask the benefits office before you change anything.
If you have kidney failure
People with end-stage renal disease can join Medicare Advantage plans, an option that opened in 2021. Check that your dialysis center and transplant hospital are in the network.
What to check before you choose
- Whether your doctors, hospitals and pharmacies are in the plan's network, and whether that is likely to change.
- Whether your drugs are on the plan's list, and at what cost tier.
- The yearly out-of-pocket limit, not just the premium.
- Which services need prior authorization or referrals.
- Coverage when you travel: Medicare Advantage covers emergencies anywhere in the U.S., but routine care is usually local.
- If you have retiree coverage from a former employer, whether joining a plan would end it.
Medicare's plan finder shows next year's plans for your ZIP code, with star ratings. Free, unbiased help is available from your State Health Insurance Assistance Program. If your income is limited, check whether Medicare Savings Programs and Extra Help can pay your premiums under either route.
Common mistakes
- Choosing a plan by premium alone, without checking the out-of-pocket limit and copays for the care you use.
- Assuming your doctors will stay in the network next year. Networks change, and plans send notices each fall.
- Dropping a Medigap policy to try Medicare Advantage without knowing whether you could buy it back.
- Leaving retiree coverage without checking whether it can be restarted.
- Ignoring the Annual Notice of Change your plan sends each September, which lists next year's costs and benefits.
Common questions
Is Medicare Advantage the same as Medicare?
It is a way to receive your Medicare benefits through a private plan. You are still in Medicare, still pay the Part B premium, and keep the right to return to Original Medicare during enrollment periods.
Can I switch back to Original Medicare?
Yes, from October 15 to December 7 each year, or from January 1 to March 31 if you are in a Medicare Advantage plan. Buying a Medigap policy at that point may require answering health questions.
Does Medicare Advantage have a yearly out-of-pocket limit?
Yes. For 2026 it cannot be more than $9,250 in network, or $13,900 for in-network and out-of-network services combined. Original Medicare has no limit unless you add Medigap.
Does Medicare cover care outside the United States?
Original Medicare generally does not. Some Medigap plans pay part of the cost of emergency care abroad, and some Medicare Advantage plans cover emergencies outside the country, so check before you travel.
Can I have Medigap and Medicare Advantage together?
No. Medigap works only with Original Medicare, and it is illegal for an insurer to sell you a Medigap policy if they know you are in a Medicare Advantage plan.
What this does not tell you
Plans, networks, premiums and drug lists differ by county and change every year. This guide compares the two kinds of coverage in general terms and cannot tell you which plan suits you.
Nobody here sells or recommends Medicare plans. For help comparing them, your State Health Insurance Assistance Program offers free, unbiased counseling, and Medicare's plan finder lists the plans in your area.
Official sources
What you can do next
Before October 15, list your doctors, hospitals and medicines, then compare plans for your ZIP code in Medicare's plan finder. Estimate your Medicare premium at your income, and if you are new to Medicare, read when to sign up first.
