Medigap vs. Medicare Advantage: Costs, Networks and the Choice at 65

They are two different ways to hold Medicare, and you pick one. With Original Medicare, the federal program pays claims directly: Part A for hospital stays, Part B for doctors and outpatient care. It pays most of the bill but leaves you the deductibles and a 20% coinsurance with no annual limit. A Medigap policy, also called Medicare Supplement Insurance, sits on top and pays some or all of that remainder. Medigap plans are standardized by letter, so a Plan G from one insurer covers the same things as a Plan G from another; only the price and service differ. Drugs come from a separate Part D plan.

Medicare Advantage, also called Part C, is a private plan approved by Medicare that replaces Original Medicare for your Part A and B benefits. Most plans include Part D drug coverage and many add some dental, vision and hearing benefits. In exchange, you usually use the plan's network, may need referrals to see specialists, and may need the plan's approval (prior authorization) before it covers certain services (Medicare.gov).

The two cannot be combined. If you are in Medicare Advantage, you cannot buy Medigap to cover your plan's cost-sharing (Medicare.gov). Either way, you keep paying the Part B premium, and either way Medicare generally does not cover care outside the U.S.

Medigap costs more in premiums and much less when you are sick; Medicare Advantage is the reverse. Start with what is the same. Everyone pays the Part B premium, $202.90 a month in 2026, and it rises with income: joint filers with 2024 modified adjusted gross income above $218,000 (single above $109,000) pay $284.10 to $689.90 a month per person, plus a Part D surcharge of $14.50 to $91.00 (CMS, 2026). The Part D surcharge applies to drug coverage inside a Medicare Advantage plan too, so IRMAA does not favor either choice. Our Medicare enrollment and IRMAA guide covers the brackets and how to appeal them.

Medicare Advantage. Three quarters of people in individual Medicare Advantage plans with drug coverage pay no premium beyond Part B, and the average extra premium is about $15 a month (KFF, 2026). You pay copays and coinsurance as you use care, up to the plan's out-of-pocket limit. For 2026, no plan may set that limit above $9,250 for in-network services or $13,900 for in- and out-of-network services combined (CMS); the average in-network limit is $5,421 (KFF). The limit covers Part A and B services only. Drugs have their own $2,100 cap.

Medigap. Premiums are set by each insurer and filed with the state, so they vary by state, ZIP code, age, sex and tobacco use, and a policy covers one person, so a couple buys two (CMS, Choosing a Medigap Policy). As a real example, the Maryland Insurance Administration's rate guide for July 2026 lists many insurers. Across its listed rates, the middle Plan G premium for a 65-year-old is about $255 a month; for an 85-year-old it is about $491 (Maryland Insurance Administration, our median of the listed rates). Your state will differ. Many states publish a similar guide, and it is the quickest way to see the real spread.

How a policy is priced matters as much as the starting premium. Insurers use one of three methods (CMS):

• •Community-rated: everyone pays the same premium regardless of age. It goes up with inflation, not with your birthday.
• •Issue-age-rated: the premium is set by your age when you buy and does not rise because you get older.
• •Attained-age-rated: the premium rises as you age. It is often cheapest at 65 and can become the most expensive later.

One tax point. After 65, you can pay Part B, Part D and Medicare Advantage premiums from a health savings account tax-free, but not Medigap premiums (IRS Publication 969). If you built a large HSA, that tilts the math a little toward the plan whose premiums it can pay; our HSA guide explains the rules.

For anyone new to Medicare since 2020, Plan G is the most complete Medigap plan you can buy, Plan N is the cheaper near-copy, and high-deductible Plan G is the budget version. Plans C and F, which also paid the Part B deductible, cannot be sold to people who became eligible for Medicare on or after January 1, 2020 (CMS).

Plan G leaves you only the Part B deductible, $283 in 2026. After that, Medicare-approved care costs you nothing more for the year. It also covers Part B excess charges: doctors who do not accept Medicare's payment as full payment may bill up to 15% above the Medicare-approved amount for most services (Medicare.gov).

Plan N pays the Part B coinsurance but charges up to $20 for some office visits and up to $50 for emergency room visits that do not lead to an inpatient admission, and it does not cover excess charges (CMS). The savings are real when you are healthy. Twenty specialist visits in a bad year would cost up to $400 in copays, far less than the premium difference in most states. The risk that matters is excess charges, which depend on whether your doctors accept assignment. Ask them.

High-deductible Plan G pays nothing until you have paid $2,950 of Medicare-covered costs in 2026, then works like Plan G (CMS). It is not sold in every state. For a reader who can absorb $2,950 in a bad year without noticing, it keeps any-doctor access at a fraction of the premium; the saving is the difference in premiums minus the deductible you actually pay.

This is where the two differ most in daily life. With Original Medicare you can use any doctor or hospital that takes Medicare anywhere in the U.S., in most cases without a referral, and you do not need approval before Medicare covers a service (Medicare.gov). Medigap follows Medicare: if Medicare pays, your policy pays its share. There is no separate network to check.

Medicare Advantage plans manage care. In an HMO you generally must use network doctors and hospitals, except for emergencies, urgent care when you are away from home and temporary dialysis away from home (Medicare.gov). PPOs let you go out of network at a higher cost, which is why the combined limit of $13,900 exists. Nearly all Medicare Advantage enrollees, 99%, are in plans that require prior authorization for some services (KFF, 2026), often for hospital stays, imaging, skilled nursing and expensive drugs given in a doctor's office. Even when a request is approved, the cost is time and uncertainty when you are least able to handle either.

Networks also change. A plan can drop a hospital system at the end of a year, and your cancer center or cardiologist may leave. You then switch plans, switch doctors, or pay more. None of this happens with Original Medicare. Before joining any Medicare Advantage plan, check that every doctor and hospital you use, and the one you would want for a serious diagnosis, is in network for the coming year.

Original Medicare with Medigap travels with you across all 50 states; Medicare Advantage covers emergencies and urgent care anywhere in the U.S. but routine care mainly near home. For snowbirds who spend four or five months in Florida or Arizona, that difference decides the question. Follow-up visits, a knee replacement or chemotherapy near your second home are routine care, not emergencies, so an HMO will generally not cover them and a PPO will charge out-of-network rates. You must also live in a Medicare Advantage plan's service area to join it (Medicare.gov).

Outside the U.S., Medicare generally pays nothing under either choice (Medicare.gov). Medigap Plans C, D, F, G, M and N include a foreign travel emergency benefit: after a $250 deductible each year, they pay 80% of the billed charges for medically necessary emergency care that begins in the first 60 days of a trip, up to a $50,000 lifetime limit (Medicare.gov). Some Medicare Advantage plans offer their own foreign emergency benefit; check the plan's Evidence of Coverage.

During your Medigap Open Enrollment Period: the 6 months starting the first month you are 65 or older and enrolled in Part B. During it, any insurer must sell you any Medigap policy it offers in your state, at the same price as a healthy applicant, without medical underwriting (CMS). The window happens once. It cannot be changed or repeated, and it starts when Part B starts even if you still have employer coverage (Medicare.gov). That is why people still working at a large employer often delay Part B: it keeps the window closed until they need it.

After the window, insurers in most states can ask about your health, charge more, or decline you, unless you have a guaranteed-issue right (CMS). A policy bought outside those protections can also exclude a pre-existing condition for up to six months, unless you had six months of continuous creditable coverage before it. The federal guaranteed-issue rights that matter most for this decision are these:

Some states go further. California, Maryland, Nevada and Oregon, among others, give people who already have a Medigap policy a yearly window around their birthday to switch to a policy with equal or lesser benefits without medical underwriting (California, Maryland, Nevada, Oregon). A few other states have their own open enrollment rules. These rules help you change Medigap policies; most do not help someone in Medicare Advantage get back into Medigap. Ask your state insurance department what applies where you live.

With Medigap you buy a separate Part D plan; with Medicare Advantage the drug coverage is usually built in. Medigap policies sold after 2005 do not include drug coverage (CMS). The Part D rules are the same either way: in 2026 no plan's deductible can exceed $615, and once your own spending on covered drugs reaches $2,100, you pay nothing more for covered drugs that year (Medicare.gov). That cap makes an expensive diagnosis far more predictable than it was before 2025.

What differs is the formulary and the pharmacy network. A stand-alone Part D plan can be chosen for your drugs alone; in Medicare Advantage the drug list comes with the medical network, so a plan with the right doctors may have the wrong formulary. Check both. And keep drug coverage continuously: going 63 days or more without Part D or other creditable drug coverage after your initial enrollment brings a late penalty for as long as you have drug coverage.

Richard and Susan both turn 65 in 2026. They have $3,100,000 invested, a paid-off house, his pension, and plan to claim Social Security at 70. Their joint 2024 MAGI was $240,000, which puts each of them in the first IRMAA tier: $284.10 a month for Part B and $14.50 on top of their drug premium. They live in a hypothetical state, and they are hypothetical too.

What is the same. Part B and the Part D surcharge cost each of them $3,583.20 a year ($284.10 + $14.50, times 12) under either choice.

Plan G path, per person. Premiums are $3,583.20 + $2,760 for Plan G + $540 for Part D = $6,883.20. In a healthy year they add the $283 Part B deductible and $200 of drugs. In a bad year it is the deductible plus the $2,100 drug cap; Plan G pays the $1,736 hospital deductible and every coinsurance.

Medicare Advantage path, per person. Premiums are just the $3,583.20. A healthy year adds $350 of copays and $200 of drugs. A bad year adds the plan's full $6,500 limit plus the $2,100 drug cap, because drugs do not count toward the medical limit.

What the numbers say. In a healthy year, Medicare Advantage saves them $6,466. In a year when Richard is seriously ill, the two paths are within a few hundred dollars. If both are ill in the same year, Plan G is $5,834 cheaper. Had their plan used the full $9,250 federal limit, Richard's bad year alone would have cost the couple $19,066 under Medicare Advantage.

For a couple with $3,100,000, none of these differences is large. What they are really choosing is access: the doctors they can see, whether a surgery needs approval, and whether care near their winter home is covered. They also have to think about age. In Maryland's 2026 rate guide, the middle Plan G rate listed for an 85-year-old is close to double the rate at 65, while the Medicare Advantage limit stays a known ceiling. Richard and Susan still choose Plan G, because they spend winters in Arizona and want the option of a specific cancer center. They budget for rising premiums rather than risk being unable to buy Medigap at 78.

To put your own premiums, deductibles and expected care into one annual figure, use our Healthcare Cost Estimator.

Medigap suits people who want freedom and predictability and can pay for it; Medicare Advantage suits people who value low premiums and are content with a local network. The table puts that into situations.

Dental, vision and hearing deserve a word. Medigap covers none of them (CMS), and the extras in Medicare Advantage are usually modest: a cleaning schedule, an allowance for glasses or hearing aids. A reader paying for implants or premium hearing aids will spend far more than those allowances either way, so they rarely justify the choice on their own. Neither option pays for long-term custodial care; that needs its own plan, covered in our long-term care planning guide.

Because the two directions are not equally open. You can leave Medigap for Medicare Advantage in any fall Open Enrollment, October 15 to December 7, and you can leave Medicare Advantage for Original Medicare then or from January 1 to March 31 (Medicare.gov). But getting Medigap back is a separate question, answered by an insurer that in most states can look at your health. The person most likely to want to switch, someone newly diagnosed and frustrated by a network, is the person least likely to pass underwriting.

The trial rights soften this for one year only. Join Medicare Advantage at 65 and you have 12 months to change your mind with any Medigap policy guaranteed. Drop a Medigap policy to try Medicare Advantage for the first time and you have 12 months to get it back. After that year, the choice is close to permanent in most states.

The exact dates depend on your birthday. Our retirement age calculator lists your Medicare eligibility date alongside every other key age, and the 2026 retirement numbers pagekeeps this year's Medicare, IRMAA and Social Security figures on one page.

1. Three months before your 65th birthday month: enroll in Parts A and B, or confirm that current employer coverage from a firm of 20 or more lets you delay Part B. The Medicare enrollment guide covers the windows and penalties.
2. Before Part B starts: list every doctor, hospital and prescription you use or would want for a serious diagnosis. Check whether the doctors accept Medicare assignment and which local Medicare Advantage networks include them.
3. Before Part B starts: get Medigap quotes from several insurers for Plan G, Plan N and high-deductible G. Ask how each is rated, for its rate increase history, and about household discounts. Look for your state's published rate guide.
4. Within 6 months of your Part B start date: buy the Medigap policy, ideally effective the same day as Part B. Apply up to a few months early so there is no gap.
5. During your Initial Enrollment Period: join a Part D plan (or a Medicare Advantage plan with drugs) chosen for your prescriptions and pharmacies.
6. If you chose Medicare Advantage at 65: put the first anniversary of your enrollment on the calendar. Decide before it whether to use your trial right.
7. Every October 15 to December 7: read your plan's Annual Notice of Change and compare Part D and Medicare Advantage plans for the next year.
8. Every December from 63 on: check your MAGI against the IRMAA brackets, since this year's income sets premiums two years out. Our Roth conversion guide shows how to size conversions around them.

• •Picking Medicare Advantage at 65 on premium alone and assuming Medigap will be available later. After the first year, it usually depends on your health.
• •Starting Part B while still covered by a large employer's plan and letting the one-time Medigap window run out unused.
• •Buying the cheapest Medigap quote at 65 without asking whether it is attained-age rated. The cheapest policy at 65 can be the most expensive at 80.
• •Dropping Medigap to try Medicare Advantage a second time. The trial right to get your policy back applies only the first time.
• •Reading the Medicare Advantage limit as a total cap. It covers Part A and B services. Drugs add up to $2,100, and out-of-network care in a PPO counts toward the higher $13,900 limit.
• •Expecting to escape IRMAA with Medicare Advantage. The Part B and Part D surcharges apply either way.
• •Choosing Plan N without checking assignment. Doctors who do not accept assignment can bill up to 15% more, and Plan N does not pay it.
• •Treating a Medicare Advantage plan as national coverage. Emergencies are covered anywhere in the U.S.; a planned surgery near your winter home may not be.
• •Canceling a Medigap policy before new coverage is confirmed, or dropping a retiree plan without learning whether you can ever get it back.