These are two fundamentally different ways to receive Medicare. With Medigap, you keep Original Medicare (Parts A and B) and add a standardized supplement policy that pays much of what Original Medicare leaves you owing; you also add a separate Part D drug plan. With Medicare Advantage (Part C), a private plan replaces Original Medicare, usually bundles drug coverage and extras, and often has a $0 additional premium — but it uses provider networks and prior authorization.
The core trade-off is freedom versus cost: Medigap costs more in premium but lets you see any Medicare provider nationwide with predictable bills; Medicare Advantage costs less up front but ties you to a network and variable copays.
Medigap vs Medicare Advantage at a glance
| Medigap | Medicare Advantage | |
|---|---|---|
| How it works | Supplements Original Medicare | Replaces Original Medicare (private plan) |
| Provider access | Any provider that accepts Medicare, nationwide | Plan network; referrals/prior auth may apply |
| Monthly premium | Higher (plus a separate Part D plan) | Often low or $0 (beyond the Part B premium) |
| Out-of-pocket predictability | High — supplement covers most cost-sharing | Lower premium but copays until you hit the plan's cap |
| Drug coverage | Separate Part D plan you choose | Usually bundled in |
| Extra benefits | None built in (medical only) | Often dental, vision, hearing, gym, etc. |
| Standardization | Federally standardized lettered plans (G, N, …) | Varies by plan and changes yearly |
Lean Medigap if…
- You want to see any doctor or hospital that takes Medicare, without networks or referrals.
- You value predictable, low out-of-pocket costs and will pay a higher premium for it.
- You travel or split time between states.
- You want coverage that doesn't change its rules year to year.
Lean Medicare Advantage if…
- A low or $0 premium and bundled extras (dental, vision, hearing) matter most.
- Your preferred providers are in the plan's network.
- You're comfortable with copays, networks, and possible prior authorization.
- You want drug coverage and medical coverage in one plan.
The bottom line
Medigap buys freedom and predictability at a higher premium; Medicare Advantage buys a lower premium and extras at the cost of networks and variable copays. A crucial catch: if you start on Medicare Advantage and later want Medigap, you may face medical underwriting and can be denied outside your one-time guaranteed-issue window — so weigh the long-term switch cost, not just this year's premium. Compare your state's plan landscape before enrolling.
Frequently asked questions
Can I have both Medigap and Medicare Advantage?+
No. It's illegal for anyone to sell you a Medigap policy if you're in a Medicare Advantage plan, because they're two different ways of getting Medicare. You choose one path. You can switch between them during valid enrollment periods, but switching back to Medigap may require medical underwriting.
Why might switching from Medicare Advantage to Medigap be hard later?+
When you first enroll in Medigap during your Medigap Open Enrollment Period (the six months after you're 65 and enrolled in Part B), insurers can't deny you or charge more for health reasons. Outside that window — for example, if you start on Medicare Advantage and later want Medigap — most states let insurers use medical underwriting, so you could be charged more or denied. That's a key reason to weigh the decision carefully at the start.
Does Medicare Advantage really cost $0?+
Many Medicare Advantage plans advertise a $0 plan premium, but you still pay your Part B premium, and you'll owe copays and coinsurance as you use care, up to the plan's annual out-of-pocket maximum. 'Low premium, pay-as-you-go' is the trade-off against Medigap's 'higher premium, few surprises.'
How do I compare plans in my state?+
Plan availability, premiums, and $0-premium access vary widely by state and county. Our Medicare Plan Landscape tool shows CMS 2026 plan counts and average premiums for each state, which is a good starting point before comparing specific plans at medicare.gov.
Related guides and tools
Jennifer Walsh
Editorial Lead, Health & Medicare
This article was researched and written by the Cover Forge USA editorial team against federal sources (NAIC, CMS, FEMA, DOL, SSA, state DOIs) and standard policy forms. Bylines organize content by topic — they do not assert individual licensure. See our editorial-policy for details.
Reviewed July 2026
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