Medicare Advantage vs. Medigap: Key Differences (2026)
Medicare Advantage and Medigap both sit on top of the same government program, yet they work in opposite ways. Medigap is extra insurance you buy to go with Original Medicare. Medicare Advantage is a private plan that takes the place of Original Medicare. You cannot have both at once, and the choice you make at 65 can be hard to reverse later. This guide lays out how each works, what they cost, when you can enroll, and where people get tripped up.
The short version
Original Medicare (Part A for hospital care, Part B for outpatient care) pays most of your bills but not all. In 2026 the Part B deductible is $283, the standard Part B premium is $202.90 a month, and the Part A deductible is $1,736 per benefit period, according to Medicare.gov. After the deductible, Part B generally leaves you with 20% coinsurance, and Original Medicare has no yearly cap on what you can owe.
That gap is what both options try to address. Medigap pays some or all of those leftover costs. Medicare Advantage wraps everything into one plan with its own copays and a yearly limit on in-network spending.
About 55% of eligible Medicare beneficiaries were enrolled in Medicare Advantage in 2026, roughly 35.2 million of 64.2 million people, based on KFF’s analysis. The rest mostly use Original Medicare, with or without a Medigap policy.
Comparison table
| Feature | Medicare Advantage (Part C) | Medigap |
|---|---|---|
| What it is | Private plan that replaces Original Medicare | Private policy that supplements Original Medicare |
| Monthly premium | Often low or $0 beyond the Part B premium | Higher, varies by plan letter, age, state and insurer |
| Doctor choice | Plan network, sometimes with referrals | Any provider that accepts Medicare |
| Cost when you use care | Copays and coinsurance set by the plan | Small or none, depending on the plan letter |
| Yearly spending cap | Yes, in-network limit set by federal rules | Not needed; the policy fills in the gaps instead |
| Prescription drugs | Usually included | Not included; you add a Part D plan |
| Dental, vision, hearing | Often offered | Not offered |
| Prior authorization | Common | Not added by the Medigap policy |
| Use across the country | Depends on plan type, emergencies covered | Works anywhere Medicare is accepted |
| Can you be turned down? | No, during valid enrollment periods | Possibly, outside protected windows |
How Medicare Advantage works
You keep paying your Part B premium and enroll in a plan run by a private insurer approved by Medicare. The plan must cover everything Original Medicare covers, though it can use its own rules for how you get that care. Most are HMOs or PPOs. HMOs usually want you to stay in network and may ask for referrals to see specialists. PPOs allow out-of-network visits at a higher price.
What you pay
Many plans charge no premium beyond Part B, which is a big part of their appeal. You pay copays for visits, tests and hospital days instead. Each plan has a yearly out-of-pocket maximum for in-network care. The federal ceiling is set each year, and for 2026 it is $9,250, though KFF found the average plan limit was well under that, near $5,400. Check the specific plan, because the range is wide.
What comes with it
Most plans bundle drug coverage. Many add dental, vision, hearing or gym benefits. The details differ a lot from plan to plan, and a benefit that sounds generous may come with an annual dollar limit.
The trade-offs
Networks change from year to year. KFF reports that nearly all Medicare Advantage enrollees, 99%, are in plans that require prior authorization for at least some services. That means the plan reviews certain care before approving it. Most requests go through, but delays and denials do happen, and appeals take effort.
How Medigap works
Medigap, also called Medicare Supplement Insurance, is sold by private insurers but standardized by plan letter. A Plan G in one company covers the same basic benefits as a Plan G from another. Only the price and the service differ. Plans in most states are labeled A, B, C, D, F, G, K, L, M and N, though some are closed to people who became eligible for Medicare in 2020 or later (Plans C and F). Massachusetts, Minnesota and Wisconsin use their own standardized formats.
Medigap pays after Original Medicare pays. Depending on the letter, it can cover Part A coinsurance, Part B coinsurance, the Part A deductible, the Part B deductible (only on plans sold to people eligible before 2020), and foreign travel emergencies. You can see any doctor or hospital that takes Medicare, anywhere in the country, with no network.
What you pay
Premiums are higher than for most Advantage plans and change with the plan letter, your age, where you live and how the insurer sets prices. Insurers price in one of three ways: community-rated, issue-age-rated, or attained-age-rated. With attained-age pricing, premiums rise as you get older. Ask which method a policy uses, since it affects the long-run cost more than the first-year quote does.
What it leaves out
Medigap does not cover prescription drugs, dental, vision or hearing. You would pair it with a separate Part D drug plan and, if you want, a standalone dental or vision plan.
Cost: how the two compare over a year
The two options shift when you pay. Medigap front-loads the cost into a higher monthly premium so that care costs very little at the counter. Medicare Advantage keeps the premium low and charges more when you use care. For someone who rarely sees a doctor, the Advantage structure can cost less across the year. For someone with a hospital stay or ongoing treatment, a cap that still reaches thousands of dollars can add up, while Medigap keeps the same year far more predictable.
Neither is cheaper in every case. Add up the premium you would pay, your likely copays, your drug costs and the out-of-pocket cap, and compare totals rather than premiums alone. Medicare.gov’s plan finder and your State Health Insurance Assistance Program (SHIP) can help with this at no charge. For general ways to trim insurance costs, see our guide on how to lower your insurance premiums.
Who each option tends to suit
Medicare Advantage often fits people who
- want a low monthly premium and are comfortable paying copays when they use care
- like having drugs, dental, vision and hearing in a single plan
- live where their doctors and hospitals are in the plan’s network
- are fine with referrals and prior authorization
Medigap often fits people who
- want to see any provider that accepts Medicare, including specialists in other cities
- travel or live in more than one state during the year
- prefer a steady, predictable cost for care and accept a larger premium for it
- are willing to buy a separate Part D plan
These are general patterns, not a recommendation for any one person. A SHIP counselor can look at your actual doctors, medicines and budget.
Enrollment windows
Initial Enrollment Period
This is the seven-month window around your 65th birthday: three months before, the month of, and three months after. You can pick a Medicare Advantage plan during this period.
Medigap Open Enrollment Period
This is the most important window for Medigap. It is a six-month period that starts the first month you are 65 or older and enrolled in Part B. During it, an insurer must sell you any Medigap policy it offers at the same price it charges others your age, whatever your health. Once it ends, in most states the insurer can ask health questions and decline you or charge more, unless you qualify for a guaranteed issue right.
Medicare Advantage windows
- Annual Enrollment Period: October 15 to December 7. You can join, drop or switch Advantage plans, with changes starting January 1.
- Medicare Advantage Open Enrollment: January 1 to March 31, for people already in an Advantage plan. You can switch to another Advantage plan or go back to Original Medicare.
- Special Enrollment Periods: triggered by events such as moving out of the plan’s area or the plan leaving Medicare.
Because it is currently October 20, 2026, the Annual Enrollment Period for 2027 coverage is open right now and ends December 7. Medigap has no such fixed yearly window, and that difference drives much of what follows.
Medigap guaranteed-issue rights
Guaranteed issue means the insurer cannot reject you, delay coverage, charge more because of health, or exclude pre-existing conditions. Federal law gives you this right in a few situations, usually with a 63-day deadline. Common ones include:
- Your Medicare Advantage plan ends or leaves your area, or you move out of its service area. You can apply starting 60 days before coverage ends and up to 63 days after. The Medigap policy cannot start until the Advantage coverage ends.
- Your employer or union group coverage that pays after Medicare ends.
- Your Medigap insurer goes bankrupt or ends your policy through no fault of your own.
- You made a trial-period switch (see below).
Some states go further than federal law. A few allow switching Medigap plans at any time or yearly, with continuous or anniversary-based windows. Your state insurance department or SHIP can tell you what applies where you live.
Switching rules: the one-way door
This section matters most, and it gets skipped in many comparisons.
Going from Medigap to Medicare Advantage
You can join a plan in any enrollment period you qualify for. But you generally must drop your Medigap policy, since an insurer is not allowed to sell you Medigap if you are in an Advantage plan. Once the Medigap policy is gone, getting it back is not guaranteed.
Going from Medicare Advantage to Original Medicare and Medigap
You can leave an Advantage plan during the Annual Enrollment Period or the January to March open enrollment, then pick up a Part D plan. Getting a Medigap policy at that point, though, is a separate question. Outside a guaranteed issue right, the insurer can use medical underwriting. Someone with a heart condition, cancer history or diabetes may be declined or quoted a much higher price.
The trial right
There is a built-in safety net. If you joined Medicare Advantage when you first became eligible at 65 and want to leave within the first 12 months, you have a guaranteed issue right to buy a Medigap policy. The same applies if you dropped a Medigap policy to try Medicare Advantage for the first time and switch back within a year. In that case you may get your old policy back if the insurer still sells it. If not, you can pick from certain other plans. The window is short, so mark the date.
Switching between Medigap plans
In most states you can apply for a different Medigap plan at any time, but the insurer may underwrite you, so a new plan is not guaranteed unless you are within a protected period or live in a state with extra protections.
Common mistakes
- Choosing by premium alone. A $0 premium plan can cost more across a bad year than a pricier one. Look at the out-of-pocket cap too.
- Missing the Medigap open enrollment period. It starts only once and does not repeat. After it closes, health questions may apply.
- Not checking the network. Confirm that your doctors, hospital and specialists are in the plan this year, and that your prescriptions are on the formulary. These change annually.
- Assuming you can switch back. Leaving Medigap for Advantage may be permanent for practical purposes if your health changes.
- Buying Medigap while in an Advantage plan. Insurers are not supposed to sell you one, and doing so can mean paying for coverage you cannot use. Medigap policies are also not compatible with each other, so you only need one.
- Forgetting Part D. Medigap has no drug coverage. A late-enrollment penalty can apply if you go without creditable drug coverage.
- Relying on extra benefits. Read the dollar limits on dental, vision and hearing before counting them as savings.
- Ignoring the yearly notice. Advantage plans change benefits and networks each year. The Annual Notice of Change arrives in the fall, which is when to read it.
Related reading
Medicare is one piece of the health coverage picture. If you are still under 65 and between coverage, our explainer on short-term health insurance covers its limits and risks. To see how private insurers compare more broadly, read best health insurance companies. Both Medicare options also cover preventive visits, which we describe in what a wellness exam is.
Frequently asked questions
Can I have Medicare Advantage and Medigap at the same time?
No. Medigap works with Original Medicare, and Medicare Advantage replaces it. Insurers may not knowingly sell you a Medigap policy while you are in an Advantage plan, and Medigap would not pay toward Advantage costs anyway.
Is Medigap or Medicare Advantage cheaper?
It depends on how much care you use. Advantage usually has lower premiums and higher costs at the time of care. Medigap has higher premiums and lower costs at the time of care. Compare the total for a typical year and for a high-use year.
Can an insurer deny me Medigap?
Not during your six-month Medigap Open Enrollment Period or when you have a guaranteed issue right. Outside those windows, in most states, insurers can use medical underwriting to decline you or charge more.
Can I switch from Medicare Advantage back to Original Medicare?
Yes. You can switch during the Annual Enrollment Period (October 15 to December 7) or the Medicare Advantage Open Enrollment Period (January 1 to March 31), or during a Special Enrollment Period. Whether you can then buy Medigap depends on your guaranteed issue rights.
Does Medigap cover prescription drugs?
No. Medigap policies sold today do not include drug coverage. You would enroll in a stand-alone Medicare Part D plan. Most Medicare Advantage plans include drug coverage.
What is the Medicare Advantage trial right?
If you joined Medicare Advantage when first eligible, or left a Medigap policy to try Advantage for the first time, you have a guaranteed issue right to return to Original Medicare and buy Medigap within the first 12 months.
Where can I get free help comparing plans?
Every state has a State Health Insurance Assistance Program (SHIP) that offers free, unbiased counseling. You can also use the plan finder on Medicare.gov or call 1-800-MEDICARE.
This article is general information, not personal insurance or financial advice. Plan rules, prices and state protections change, so confirm details with Medicare.gov, your state’s SHIP or a licensed professional.