Medigap and Medicare Advantage Are Not the Same — Here's What Sets Them Apart

No, Medigap and Medicare Advantage are two completely different ways to cover costs that Original Medicare does not pay

Both are add-on plans, but they work in opposite directions. Medicare Advantage (also called Part C) replaces Original Medicare entirely — you use it instead of Medicare Parts A and B. Medigap (also called Supplemental Insurance) works alongside Original Medicare — you keep Parts A and B and add Medigap on top to cover what Medicare leaves unpaid. The choice between them shapes which doctors you can see, how much you pay out of pocket, and what happens if you change your mind later.

Key Takeaways

Medicare Advantage replaces Original Medicare and typically includes prescription drug coverage, but limits you to in-network doctors and requires referrals for specialists.
Medigap supplements Original Medicare and lets you see any doctor who accepts Medicare, but does not cover prescription drugs — you need a separate Part D plan for that.
Medicare Advantage plans have annual out-of-pocket limits; Medigap plans do not, but Medigap premiums are usually higher than Advantage premiums.
You can switch from Medigap to Medicare Advantage anytime, but switching from Advantage to Medigap is restricted to specific enrollment periods and may require medical underwriting.
The best choice depends on whether you prefer lower premiums and integrated drug coverage (Advantage) or freedom to choose any Medicare doctor (Medigap).

How Medicare Advantage Works

Medicare Advantage is a complete replacement for Original Medicare. When you enroll in an Advantage plan, you give up your Medicare card and use the Advantage plan's card instead. The plan is run by a private insurance company, not Medicare directly.

Most Medicare Advantage plans include prescription drug coverage (Part D) built in, so you do not need a separate drug plan. Many also add benefits Original Medicare does not cover — dental, vision, hearing, or gym memberships. The trade-off is that you must use doctors and hospitals in the plan's network, and you usually need a referral to see a specialist. If you go out of network, you pay much more or the plan may not cover it at all. Plans also have an annual out-of-pocket maximum — once you hit it, the plan pays 100 percent of covered services for the rest of that year.

Premiums for Medicare Advantage are often lower than Medigap premiums, and some plans have zero premium. However, you typically pay a copay or coinsurance each time you use a service.

How Medigap Works

Medigap is a supplement. You keep your Original Medicare coverage (Parts A and B), and Medigap covers some or all of the costs Medicare does not pay — deductibles, coinsurance, and copays. You use your Medicare card to see any doctor or hospital that accepts Medicare, anywhere in the country. There are no networks, no referrals required, and no prior authorization.

Medigap plans are standardized by the federal government. There are ten different plan types (A, B, C, D, F, G, K, L, M, N), and each plan covers the same benefits no matter which insurance company sells it. The difference between plans is which costs they cover and how much. For example, Plan F covers nearly everything Medicare does not; Plan A covers less.

Medigap does not include prescription drug coverage. If you want drug coverage, you must enroll in a separate Medicare Part D plan. Medigap premiums are usually higher than Medicare Advantage premiums, and unlike Advantage plans, Medigap has no annual out-of-pocket limit — you could theoretically pay indefinitely if you use many services.

Network Restrictions and Doctor Choice

This is often the deciding factor. With Medicare Advantage, your choice of doctors is limited to the plan's network. If your longtime doctor is not in the network, you either switch doctors or pay out of network. Specialist visits usually require a referral from your primary care doctor first.

With Medigap, you can see any doctor in the country who accepts Medicare. No referrals, no networks, no "in-network" versus "out-of-network" pricing. If you travel frequently, live part of the year in two places, or have a specialist you want to keep, Medigap gives you that freedom.

Prescription Drug Coverage

Medicare Advantage plans almost always include Part D drug coverage. When you enroll in Advantage, your drugs are covered through that plan, and you do not buy a separate Part D plan.

Medigap does not cover drugs at all. You must enroll in a standalone Part D plan. This means two separate monthly premiums — one for Medigap and one for Part D — but it also means you can choose your drug plan independently of your supplement plan. You can change your Part D plan every year during the annual enrollment period without changing your Medigap plan.

Costs: Premiums, Deductibles, and Out-of-Pocket Limits

Medicare Advantage premiums are typically lower than Medigap premiums — sometimes zero. However, Advantage plans have copays and coinsurance for each service, and these add up. The good news is that Advantage plans have an annual out-of-pocket maximum. Once you hit that limit (which varies by plan but is set by Medicare), the plan pays 100 percent of covered services for the rest of the year.

Medigap premiums are usually higher, but once you pay the premium, you have predictable costs. Depending on which Medigap plan you choose, you may have little or no copay when you see a doctor. However, Medigap has no out-of-pocket limit. If you use many services in a year, your costs could exceed what you would pay with Medicare Advantage.

The right choice depends on your health. If you are generally healthy and want low premiums, Medicare Advantage may cost less. If you use many services or want to avoid surprises, Medigap's predictability may be worth the higher premium.

Switching Between Plans

Switching from Medigap to Medicare Advantage is straightforward. You can do it during the annual Medicare enrollment period (October 15 to December 7) or during your Initial Enrollment Period if you are newly may be able to access for Medicare. You straightforward enroll in the Advantage plan, and your Medigap coverage ends.

Switching from Medicare Advantage to Medigap is harder. You can switch during the annual enrollment period, but if you want to switch at other times, you may not be able to. More importantly, when you switch from Advantage to Medigap, the insurance company can require medical underwriting — they can deny you, charge you more, or exclude pre-existing conditions. This is called a may provide issue period, and it only applies in certain situations, such as if your Advantage plan is leaving the market or you move out of the service area. Outside those situations, the insurance company can reject your process.

This asymmetry matters. If you choose Medicare Advantage and later regret it, you may not be able to switch to Medigap without medical underwriting. If you choose Medigap first, you can always switch to Advantage without penalty.

Frequently Asked Questions

Can I have both Medicare Advantage and Medigap at the same time?

No. Medicare does not allow it. You must choose one or the other. If you enroll in Medicare Advantage, your Medigap coverage automatically ends. If you enroll in Medigap, you cannot also have Advantage.

Which plan covers more?

It depends on the specific plans. Some Medicare Advantage plans cover dental, vision, and hearing — benefits Original Medicare and Medigap do not cover. However, Medigap covers more of the standard Medicare costs (deductibles and coinsurance) than most Advantage plans do. Medigap also gives you access to any Medicare doctor, while Advantage limits you to a network.

What if I move to a different state?

Medicare Advantage plans are regional — they only work in specific counties or service areas. If you move out of your plan's service area, your coverage ends, and you must choose a new plan. Medigap works nationwide, so you can move anywhere and keep the same coverage.

Do I need Part D if I have Medicare Advantage?

No. Medicare Advantage plans include Part D drug coverage. You do not buy a separate Part D plan. If you have Medigap, you must buy a separate Part D plan if you want drug coverage.

Which is cheaper overall?

It varies by person and by year. Medicare Advantage premiums are usually lower, but you pay copays for each service. Medigap premiums are higher, but copays are lower or zero. If you are healthy and use few services, Advantage is often cheaper. If you use many services, Medigap's predictability may save you money overall. Compare the specific plans available to you in your area.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.