Two different ways to fill the same gap
Original Medicare covers roughly 80% of approved costs with no annual ceiling. Both Medicare Advantage & Medicare Supplement exist to handle that remaining exposure — they just do it in opposite ways. Advantage caps your spending with copays & an out-of-pocket maximum inside a network. A Supplement pays down your share of Original Medicare costs at any provider nationwide that accepts Medicare.
Where the money goes
- Medicare Advantage: low or $0 monthly premium; you pay copays as you use care until you hit the plan's out-of-pocket maximum.
- Medicare Supplement: higher predictable monthly premium; very little or nothing at the point of care, depending on the plan letter.
- Both: you keep paying your Part B premium either way.
Networks & travel
Advantage plans are county-based & network-based. If you split the year between two states, see specialists at out-of-area centers, or travel often, a Supplement typically fits better. If you get all your care locally & value the extra benefits, Advantage often wins on total cost.
Prescription drugs
Most Medicare Advantage plans include Part D. With a Supplement you buy a standalone Part D plan separately — which also means you can change drug plans each year without touching your medical coverage.
The switching rule most people don't know
Choosing Medicare Advantage first is not permanent, but it is not fully reversible either. You can drop back to Original Medicare during AEP or Advantage Open Enrollment, but buying a Medicare Supplement at that point usually means medical underwriting in most states. Health conditions developed since you turned 65 can lead to a decline. Your Medigap Open Enrollment Period — six months starting when you are 65 & enrolled in Part B — is the one time you are guaranteed acceptance.
Quick decision guide
- Choose a Supplement if: you travel or snowbird, want any Medicare provider, prefer predictable budgeting, or have complex ongoing conditions.
- Choose Advantage if: your doctors are in network, you want dental/vision/hearing extras, & you prefer a low premium with copays as you go.
Frequently asked questions
Is a $0 premium Medicare Advantage plan really free?+
The plan premium is $0, but you still pay your Part B premium plus copays & coinsurance as you use care, up to the plan's annual out-of-pocket maximum.
Which Medicare Supplement plan letter is most popular?+
Plan G for people newly eligible, & Plan N for those who want a lower premium in exchange for small office-visit copays. Plan F is only available to people eligible for Medicare before January 1, 2020.
For educational purposes only. Alliance Global Insurance Group is not affiliated with or endorsed by Medicare.gov or the U.S. government. Plan availability, costs & rules vary by county & change annually — confirm details with a licensed advisor or at Medicare.gov.