Medicare Advantage vs. Medicare Supplement: how to compare
“Should I get an Advantage plan or a Supplement?” is probably the most common question people ask when they reach Medicare — and the most common place to get confused, because the two products solve the same problem in opposite ways. Original Medicare leaves you exposed to deductibles and an uncapped 20 percent coinsurance. Medicare Advantage replaces how you receive your benefits; a Medicare Supplement fills in the gaps of the benefits you already have.
This guide lays out how each works, where each tends to fit, and the comparison questions that matter more than the premium. It is general education — for your complete set of options, use Medicare.gov, 1-800-MEDICARE, or your local SHIP, and for plan-specific details talk to a licensed agent.
How Medicare Advantage works
A Medicare Advantage plan (Part C) is offered by a private insurer and delivers your Part A and Part B benefits — and usually Part D drug coverage — in one plan. Most plans use networks: HMOs generally require you to use network providers and may require referrals, while PPOs let you go out of network for a higher cost. Many plans add benefits Original Medicare does not cover, like dental, vision, hearing, or fitness programs.
Cost-wise, Advantage plans tend to have low or even $0 premiums on top of your Part B premium, with copays as you use care, prior-authorization requirements for some services, and an annual out-of-pocket maximum that caps your exposure. Benefits, networks, and drug formularies can change every January 1, so an annual review during the fall enrollment period is part of owning one of these plans.
How Medicare Supplement (Medigap) works
A Medicare Supplement policy works alongside Original Medicare: Medicare pays its share first, then your Medigap policy helps pay some or all of what is left, depending on the lettered plan you choose (Plan G and Plan N are common choices for people new to Medicare today). There are no networks — you can see any provider in the country that accepts Medicare, and referrals are never required.
The trade-offs: Medigap premiums are higher than typical Advantage premiums and tend to rise with age depending on how the policy is rated. Medigap policies also do not include drug coverage, so most people pair one with a standalone Part D plan. And outside your one-time six-month open enrollment window (which starts when you are 65+ and enrolled in Part B), insurers in most states can ask health questions and decline coverage — so the path you pick early matters.
The five questions that actually decide it
First: provider freedom. Do you want to keep any doctor who accepts Medicare anywhere in the country (Supplement), or are you comfortable inside a network with plan rules (Advantage)? Second: predictability versus pay-as-you-go. Supplements trade a higher fixed premium for few surprises; Advantage trades a low premium for copays and the possibility of hitting a multi-thousand-dollar out-of-pocket maximum in a heavy-care year.
Third: travel. If you split the year between states or travel often, the network question gets louder. Fourth: drugs. Either path needs a drug answer — built into most Advantage plans, separate Part D alongside a Supplement — and your specific medication list should be checked against any formulary. Fifth: the long game. Moving from Advantage to a Supplement later may require passing health underwriting, while moving the other direction is generally easier.
Common misconceptions
“Medicare Advantage is free.” A $0 premium is not $0 cost — you still pay your Part B premium plus copays, and the out-of-pocket maximum is the number to study. “Medigap covers everything.” It covers cost-sharing for Medicare-approved services; it does not add dental, vision, hearing, or drug coverage. “I can switch any time.” Enrollment periods control when changes happen, and Medigap underwriting can limit your options outside protected windows.
The honest summary: people who prioritize provider freedom and predictable costs often lean Supplement; people who prioritize lower monthly outlay and bundled extras often lean Advantage. Your doctors, medications, budget, travel, and health outlook tip the scale. An independent licensed agent can run the plans they represent against your specifics — find one in your area through our directory, or use Medicare.gov's Plan Finder to compare on your own.
Frequently asked questions
Can I have both a Medicare Advantage plan and a Medicare Supplement?
No. It is illegal for someone to sell you a Medigap policy while you are enrolled in a Medicare Advantage plan, and a Supplement would not pay alongside one anyway. You choose one path at a time.
Which costs more?
Supplements usually cost more per month but limit surprises; Advantage plans usually cost less per month but charge copays as you use care, up to an annual out-of-pocket maximum. Total yearly cost depends on how much care you use.
Can I switch from Advantage to a Supplement later?
Sometimes — but outside protected windows, Medigap insurers in most states can ask health questions and may decline coverage. A few situations (like trial rights) give guaranteed-issue protection; check your state's rules.
This is general education, not personalized advice, and plan details change every year. For all of your options, contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Assistance Program (SHIP) at shiphelp.org.