The Core Difference Between Medigap and Medicare Advantage
Medigap and Medicare Advantage are two different ways to pay for care once you have Original Medicare. They work in opposite directions. Original Medicare (Part A and Part B) covers hospital and doctor visits, but leaves you paying deductibles, copays, and coinsurance. Medigap is an insurance policy you buy from a private company to cover those gaps — it works alongside Original Medicare. Medicare Advantage is a complete replacement for Original Medicare sold by private insurers; it bundles hospital, doctor, and often prescription drug coverage into one plan, usually with a network of doctors you must use.
The choice between them shapes how much you pay upfront, which doctors you can see, and what happens if you need care outside your home state. Neither is "better" — the right one depends on your health, your doctors, and how much predictability you want in your costs.
Key Takeaways
- Medigap supplements Original Medicare and lets you see any doctor nationwide who accepts Medicare; Medicare Advantage replaces Original Medicare and usually limits you to an in-network provider list.
- Medigap has no yearly deductible but charges a monthly premium; Medicare Advantage often has a low or zero monthly premium but includes deductibles and copays for each service.
- Medigap covers emergency care anywhere in the United States and abroad; Medicare Advantage typically covers emergencies only within the United States and may not cover care outside your plan's service area.
- You can switch from Medicare Advantage to Medigap during the annual open enrollment period, but switching from Medigap to Medicare Advantage may require medical underwriting depending on your state.
- Medigap plans are standardized by the federal government (Plan A, Plan B, Plan G, etc.); Medicare Advantage plans vary by insurer and region and may include dental, vision, or hearing benefits.
How Medigap Works and What It Covers
When you have Original Medicare plus Medigap, you keep your Medicare card and use it at any hospital or doctor's office in the United States that accepts Medicare — which is nearly all of them. You pay your doctor's bill as usual, and then Medigap steps in to cover the deductible, copay, or coinsurance you would otherwise owe. You do not submit claims yourself; the billing happens automatically between Medicare, Medigap, and the provider.
Medigap plans are labeled A through N (some states do not offer all letters). Each letter covers a different combination of costs. Plan G, for example, covers the Part B deductible, copays for doctor visits, and coinsurance for hospital stays. Plan N covers most of the same things but charges a copay for doctor visits and emergency room visits. The federal government sets what each letter must cover, so Plan G from one insurance company covers exactly the same things as Plan G from another — you are only choosing the insurer and the monthly premium.
Medigap premiums vary by age, location, and the plan letter you choose. You pay the premium every month regardless of whether you use care. There is no yearly deductible to meet before coverage starts. If you travel or move, your Medigap plan works the same way in every state.
How Medicare Advantage Works and What It Costs
Medicare Advantage is a managed care plan. You choose a plan offered by an insurance company (UnitedHealth, Humana, Aetna, and others), and that plan becomes your only Medicare coverage. You do not use your Original Medicare card; you use the Medicare Advantage plan's card instead. The plan covers hospital, doctor, and usually prescription drug benefits all in one, and the federal government pays the insurer a fixed amount per month to manage your care.
Most Medicare Advantage plans have a monthly premium of zero or very low — sometimes $0 to $50 per month — because the insurer receives payment from Medicare itself. However, you pay when you use care: a copay to see a doctor (often $20 to $50), a copay for urgent care or the emergency room, and a deductible before certain services are covered. The total of all your copays and deductibles in a year cannot exceed a yearly out-of-pocket maximum, which varies by plan but is capped by federal law.
Medicare Advantage plans almost always require you to use doctors and hospitals within their network. If you see an out-of-network provider, you pay more or the plan may not cover it at all. Some plans include dental, vision, hearing, or fitness benefits that Original Medicare and Medigap do not cover. Prescription drugs are included in the plan, not purchased separately.
Comparing Costs: Premiums, Deductibles, and Out-of-Pocket Limits
| Cost Factor | Medigap | Medicare Advantage |
|---|---|---|
| Monthly Premium | $100–$300+ depending on plan and age | $0–$50 (often $0) |
| Yearly Deductible | None (Plan A has Part B deductible only) | $0–$500+ per service type |
| Doctor Visit Copay | $0 (covered by Medigap) | $20–$50 per visit |
| Out-of-Pocket Maximum | None (you pay premiums only) | $6,700–$7,550 per year (federal cap) |
| Prescription Drug Coverage | Not included; buy Part D separately | Included in plan |
The math depends on how often you see a doctor. If you rarely use care, Medicare Advantage's low or zero premium saves you money upfront. If you see doctors frequently or have multiple chronic conditions, Medigap's lack of copays and deductibles often costs less over the year, even though the monthly premium is higher. The out-of-pocket maximum in Medicare Advantage protects you if you have a major health event, but Medigap offers no such cap — you pay the premium every month, period.
To estimate your own costs, list the doctors you see regularly and the services you use (lab work, imaging, specialists), then call plans you are considering and ask what you would pay for those specific visits and services. A plan that looks cheap on paper may cost more once you factor in your actual care patterns.
Network Restrictions and Travel Coverage
Medigap has no network. You can see any doctor, specialist, or hospital in the United States that accepts Medicare. If you travel, move, or split time between states, your coverage does not change. Some Medigap plans (Plan C and Plan D) include coverage for emergency care outside the United States — typically 80 percent of costs up to a lifetime limit of $50,000.
Medicare Advantage plans have a defined service area, usually a county or region. You must use doctors and hospitals in that network for routine care. If you travel outside your service area, you can use any Medicare provider for emergency care, but non-emergency care is not covered. If you move permanently outside your plan's service area, you lose the plan and must choose a new one. This makes Medicare Advantage less flexible if you travel frequently or split time between homes.
When You Can Switch Between Plans
You can change plans once a year during the Annual Enrollment Period, which runs October 15 through December 7. During this window, you can switch from Medicare Advantage to Medigap, from Medigap to Medicare Advantage, or from one Medicare Advantage plan to another. The change takes effect January 1.
If you switch from Medigap to Medicare Advantage, you may face medical underwriting in some states — meaning the insurance company can deny you or charge more based on your health history. If you switch from Medicare Advantage to Medigap, you have a may provide right to buy a Medigap plan without underwriting, but only if you are switching during the Annual Enrollment Period or within 63 days of losing your Medicare Advantage plan. Outside these windows, an insurer can refuse to sell you Medigap or charge a higher premium.
There are also special enrollment periods if you move, lose employer coverage, or experience other may have access to events. These allow you to switch plans outside the annual window.
Which Plan Type Might Fit Your Situation
Choose Medigap if you have a preferred doctor or specialist you want to keep seeing, you travel frequently, you want predictable costs with no deductibles or copays, or you are willing to pay a higher monthly premium for simplicity. Medigap works well for people with multiple chronic conditions who see doctors often, because the lack of copays keeps total costs down.
Choose Medicare Advantage if you want a low monthly premium, you do not mind using a network of doctors, you are generally healthy and do not expect high medical costs, or you want dental, vision, or hearing coverage included. Medicare Advantage also works well if you have limited income and may have access to for cost-sharing reductions, which lower your copays and deductibles.
If you are unsure, you can start with Medicare Advantage when you first turn 65, then switch to Medigap during the next Annual Enrollment Period if the network feels too restrictive. You have the flexibility to change your mind once per year.
Frequently Asked Questions
Can I have Medigap and Medicare Advantage at the same time?
No. You must choose one or the other. If you enroll in Medicare Advantage, your Original Medicare coverage ends. If you later switch back to Original Medicare, you can buy Medigap. You cannot hold both simultaneously because they serve the same purpose — to cover costs that Original Medicare does not.
Do I need to buy Part D prescription drug coverage if I have Medigap?
Yes. Medigap does not include prescription drugs. You must buy a separate Part D plan from a private insurer. Medicare Advantage plans include prescription drug coverage, so you do not buy Part D separately. If you have Medigap and do not buy Part D when you first become may be able to access, you may pay a penalty if you enroll later.
What happens to my Medigap coverage if I move to a different state?
Your Medigap plan continues to work in the new state. The same plan letter covers the same benefits everywhere. Your premium may change based on your new location, and you should contact your insurer to update your address, but your coverage does not lapse or change.
Can I use my Medicare Advantage plan if I travel outside the United States?
Medicare Advantage covers emergency care only within the United States. If you need non-emergency care while traveling abroad, the plan will not cover it. Some Medigap plans include emergency coverage outside the United States, which is one reason people with frequent international travel choose Medigap over Medicare Advantage.
Is one plan type cheaper than the other?
It depends on your health and how often you use care. Medicare Advantage usually has a lower monthly premium but higher copays and deductibles. Medigap has a higher monthly premium but no copays or deductibles. If you are healthy and rarely see a doctor, Medicare Advantage is usually cheaper. If you have chronic conditions and see doctors frequently, Medigap often costs less overall.