Medicare Advantage vs. Medigap: How to Choose

MoneyBy M. E. Hart9 min readUpdated 2026-07-19

Medicare Advantage bundles hospital, medical, and usually drug coverage into one private plan with a low or even $0 premium, but adds a network, referrals, and copays up to a yearly out-of-pocket maximum. Medigap pairs with Original Medicare: a higher monthly premium, but any doctor in the country who takes Medicare and almost no surprise bills. Switching from Advantage to Medigap later usually requires medical underwriting, so the easy time to choose Medigap is when you first enroll — a choice most people make once.

Quick answer

Medicare Advantage bundles your hospital, medical, and usually drug coverage into one private plan with a low (sometimes $0) premium, extra perks like dental and vision, but a provider network, referrals, and an out-of-pocket maximum you could hit in a bad year. Medigap pairs with Original Medicare, costs a higher monthly premium, but lets you see any doctor who takes Medicare with almost no surprise bills and no networks. Advantage rewards good health and tight budgets; Medigap buys predictability and freedom. The catch: switching from Advantage to Medigap later often requires medical underwriting, so the easy time to choose Medigap is when you first enroll.

The core difference in one paragraph

With Medicare Advantage (Part C), you get your Medicare benefits through a single private plan. It usually bundles in prescription drugs and extras like dental or vision, often for a very low premium — but you're steered to the plan's network of doctors and hospitals, may need referrals, and pay copays as you go up to a yearly out-of-pocket limit. With Medigap (a Medicare Supplement policy), you keep Original Medicare and add a supplement that pays most of the deductibles and coinsurance Original Medicare leaves you. You pay a higher monthly premium, but you can see any provider in the country who accepts Medicare, with no networks and very few surprise bills. One key rule up front: you can't use both — Medigap only works alongside Original Medicare, never with a Medicare Advantage plan.

A plain-English guide, not medical or insurance advice

This article explains how Medicare's rules generally work so you can ask better questions and compare with confidence — it isn't medical, legal, or insurance advice, and the specifics depend on your plans, your state, and your health. Confirm everything against the primary sources linked below, and for a personal recommendation, talk to your State Health Insurance Assistance Program (SHIP) counselor — free, unbiased, and not selling anything.

How Medicare Advantage works

Premium: Often low or $0 — but you still pay your Part B premium ($202.90 a month in 2026).
Costs when you use it: Copays and coinsurance for visits, tests, and stays, until you reach the plan's annual out-of-pocket maximum. In a healthy year you may pay little; in a year with surgery or a hospital stay, you could pay thousands.
Networks: HMOs and PPOs with defined networks. Out-of-network care costs more or isn't covered, and networks change yearly.
Referrals and prior authorization: Many plans require a referral to see a specialist and prior approval for certain services or drugs.
Extras: Often includes dental, vision, hearing, and drug coverage in one card — the main reason the premiums stay low.

How Medigap works

Premium: A higher monthly premium on top of your Part B premium — the price of predictability.
Costs when you use it: Very low and predictable. A plan like G covers most of what Original Medicare doesn't, so you rarely face a surprise bill.
No networks: See any doctor or hospital in the U.S. that accepts Medicare. No referrals.
Standardized plans: Medigap policies are federally standardized and sold by letter — Plan A, B, D, G, K–N, and more. A plan with a given letter offers the same benefits no matter which company sells it, so you can shop on price and service.
Drugs are separate: Medigap doesn't include prescription coverage — you add a standalone Part D plan.

About Plan F, Plan G, and Plan N

Plan G covers the most of any plan available to people newly eligible for Medicare today, and a common pick. Plan N costs a bit less in exchange for small copays — up to $20 for some office visits and up to $50 for an emergency room visit that doesn't lead to admission. Plan C and Plan F are closed to anyone who became eligible for Medicare on or after January 1, 2020; if you were eligible before then, you may still be able to buy Plan F. High-deductible versions of Plan F, G, and J carry a $2,950 deductible in 2026 before full coverage kicks in.

Which one fits you?

There's no universally right answer — it's a trade between price and freedom. A few honest generalizations:

Medicare Advantage tends to fit if you…

Want the lowest possible premium and are comfortable with copays when you need care.
Are in good health and don't expect heavy medical use.
Value bundled dental, vision, and drug coverage on one card.
Are happy staying with local, in-network doctors and don't travel much for care.

Medigap tends to fit if you…

Want predictable costs and few surprise bills, even at a higher monthly premium.
Have a chronic condition or expect significant care and want to cap the financial risk.
Want to keep specific doctors, travel often, or spend part of the year in another state.
Would rather not deal with referrals, networks, or prior authorization.

The switching trap most people don't see coming

Here's the part that makes this decision weightier than it looks. When you're first eligible for Medicare, you get a one-time Medigap Open Enrollment window — six months — during which an insurer must sell you any Medigap policy at the best price, regardless of your health. That's guaranteed-issue. But if you start on Medicare Advantage and try to switch to Medigap years later, in most states the insurer can put you through medical underwriting — they can charge you more, or turn you down, based on your health history. So the moment it's easiest and cheapest to choose Medigap is right at the start, while you're healthy. Plenty of people pick Advantage for the low premium, develop a condition, and then find the door to Medigap has narrowed. That doesn't make Advantage wrong — it makes the timing something to decide on purpose, not by default.

You can change your mind during the fall open enrollment window — switching between Advantage and Original Medicare is allowed — but adding a Medigap policy is the piece that can require underwriting. For free, unbiased help running the numbers for your situation, your State Health Insurance Assistance Program (SHIP) is the place to go.

Once you've settled the big structural question, the next step is drug coverage: our guide on how to compare Medicare Part D plans shows what to weigh beyond the premium, and the open enrollment checklist covers what to gather before you shop.

Common questions

Can I switch from Medicare Advantage back to Original Medicare if I get sick?

You can switch back to Original Medicare — but that is not the same as being able to buy a Medigap policy to go with it. Outside a guaranteed issue right, Medicare says an insurance company is allowed to deny you a Medigap policy if you don’t meet its medical underwriting requirements, and you may pay more or have fewer plans to choose from. A few states give residents broader rights than federal law does, so check with your State Insurance Department before you assume the door is closed.

I joined a Medicare Advantage plan at 65 and I hate it. Is it too late to get Medigap?

Not if you’re still inside your first year. Medicare gives you a trial right: if you joined a Medicare Advantage plan when you were first eligible for Medicare and you decide within that first year to switch to Original Medicare, you can buy any Medigap policy sold in your state, with no underwriting. You can apply as early as 60 days before your coverage ends and no later than 63 days after it ends — miss that window and the protection is gone.

I dropped my Medigap policy to try Medicare Advantage. Can I get it back?

Yes, if this was your first time in a Medicare Advantage plan and you’ve been in it less than a year. That’s the second federal trial right: you can repurchase the same Medigap policy you had before, if the same company still sells it. If it isn’t available, you can buy Medigap Plan A, B, C, D, F or G sold in your state (Plans C and F only if you were eligible for Medicare before January 1, 2020). Apply 60 days before your coverage ends or no more than 63 days after.

Can I have both a Medicare Advantage plan and a Medigap policy?

No — you can have one or the other, never both. Medicare says it’s illegal for anyone to sell you a Medigap policy while you’re in a Medicare Advantage plan unless you’re switching back to Original Medicare, and a Medigap policy can’t be used to pay your Advantage plan’s copayments, deductibles or premiums. If someone is trying to sell you one anyway, that’s a red flag, not a deal.

What happens if I just stay on Original Medicare and don’t buy anything extra?

You’re covered, but with no ceiling on what a bad year can cost you. Medicare states plainly that there’s no yearly limit on what you pay out of pocket unless you add a Medigap policy or join a Medicare Advantage plan — so you keep owing the Part A hospital deductible each benefit period ($1,736 in 2026) and generally 20% of the cost of each covered Part B service, with no cap. You’d also have no drug coverage, which starts a permanent Part D late enrollment penalty of 1% per month once you’ve gone 63 days or more without creditable drug coverage.

Which one actually costs less over the years — Advantage or Medigap?

Nobody can tell you in advance, because the answer depends on how much care you end up needing. Medicare Advantage usually has the lower monthly premium, but you pay copays and coinsurance as you go, up to the plan’s yearly out-of-pocket maximum — and that maximum, the drug list and the network can all change every January. Medigap costs more every month whether you use it or not, and buys you predictability instead. Advantage tends to win in healthy years; Medigap tends to win in the expensive ones.

If I go with Medigap, how do I get my prescriptions covered?

You buy a separate Medicare drug plan (Part D). Medigap policies sold since 2005 don’t include prescription drug coverage, so Original Medicare plus Medigap leaves a drug gap you have to fill yourself. Don’t skip it because you take few medications now — going 63 days or more without creditable drug coverage adds a 1% per month penalty to your Part D premium for as long as you have it.

I’ve heard Plan F is the best one. Can I still buy it?

Only if you were eligible for Medicare before January 1, 2020. Plans C and F are closed to anyone new to Medicare on or after that date. If you’re newly eligible, Plan G is the closest widely available equivalent, and Plan N trades a lower premium for small copays. Every policy with the same letter covers the same basic benefits no matter which company sells it — so once you pick a letter, price and the company’s service record are what’s left to compare.

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