Medicare Advantage vs Medigap: two paths, different trade-offs
TL;DR: Medicare Advantage bundles coverage through a private plan, usually with networks and an annual out-of-pocket limit, often at a low premium. Original Medicare plus Medigap costs more in premiums but lets you see any provider that takes Medicare. Your six-month Medigap open enrollment window is the key timing issue.
Educational only, not tax, legal, or investment advice. Examples are illustrations, not predictions. Rules and limits change; verify current figures and talk to a qualified professional about your situation.
Two Medicare paths; one has a network, the other has a premium. At 65 most people face a fork. Down one road: Original Medicare (Parts A and B) plus a Medigap supplement and a Part D drug plan. Down the other: a Medicare Advantage plan (Part C), offered by private insurers, which replaces Original Medicare's way of paying for care and usually includes drug coverage.
Neither is universally better. The choice turns on networks, travel, health, budget and timing. This comparison lays out the differences using Medicare.gov rules as of Oct 2026.
CPA Warning Label: You can usually switch from Medigap to Advantage easily. Switching back later can require passing medical underwriting. Choose like the door only swings one way.
Coverage models
Original Medicare plus Medigap. Medicare pays its share of approved costs directly. A Medigap policy, sold by private insurers in standardized lettered plans, pays some or all of the remaining deductibles, coinsurance and copayments. You add a separate Part D plan for drugs. Medigap plans of the same letter offer the same basic benefits regardless of insurer; price differs.
Medicare Advantage. A private plan approved by Medicare covers your Part A and B services, typically with its own copays and coinsurance, and an annual in-network out-of-pocket limit. Most plans include Part D drug coverage, and many add extras such as dental, vision or hearing benefits. You still pay the Part B premium ($202.90 a month in 2026 for most people), plus any plan premium.
You can't use Medigap with Medicare Advantage; Medigap only works with Original Medicare.
Networks
Original Medicare is accepted by most doctors and hospitals across the U.S. With Medigap, you can generally see any provider who accepts Medicare, with no referrals.
Medicare Advantage plans usually use networks: HMOs generally require in-network providers and referrals; PPOs allow out-of-network care at higher cost. Networks can change during the year, and plans may require prior authorization for some services.
For early retirees who travel, split time between states, or want access to specific specialists or academic medical centers, network design matters a lot. Check every doctor and hospital you care about before choosing a plan.
Guaranteed issue windows
Medicare.gov describes the Medigap Open Enrollment Period as six months that start the first month you have Part B and are 65 or older. During this period, an insurer generally can't use medical underwriting, meaning it can't refuse to sell you a policy or charge more because of health conditions. It doesn't repeat.
After the window, insurers in most states can use medical underwriting. Some situations create guaranteed issue rights, such as losing other coverage or certain trial-right situations for people who try Medicare Advantage when first eligible. A few states have broader rules. But the general pattern holds: Medigap is easiest to buy at the start.
Medicare Advantage, by contrast, can usually be joined or changed during the annual open enrollment period, October 15 to December 7, without health questions. There's also a Medicare Advantage open enrollment period from January 1 to March 31 for switching plans or returning to Original Medicare.
Costs
Cost comparisons depend heavily on location and plan, so think in structures rather than prices:
| Original Medicare + Medigap + Part D | Medicare Advantage | |
|---|---|---|
| Monthly premiums | Part B + Medigap + Part D; Medigap often the largest | Part B + plan premium, sometimes $0 |
| Costs when you use care | Low to very low, depending on the Medigap plan | Copays and coinsurance per service |
| Annual out-of-pocket cap | None in Original Medicare itself; Medigap fills most gaps | Yes, in-network limit set by each plan |
| Predictability | High: mostly premiums | Lower: depends on use |
| Extras (dental, vision) | Not included | Often included in some form |
For 2026, Original Medicare's Part B deductible is $283 and the Part A hospital deductible is $1,736 per benefit period, with daily coinsurance of $434 for days 61 to 90. Without supplemental coverage, a long hospital stay can be expensive; that's the gap Medigap fills.
Illustration: a healthy 66-year-old compares two paths. Path A: Part B $202.90, a Medigap plan at an assumed $180, and a Part D plan at an assumed $40, about $423 a month or $5,074 a year, with minimal costs at the doctor. Path B: Part B plus a $0-premium Advantage plan, $2,435 a year, but with copays, and an assumed in-network out-of-pocket limit of $6,000. In a quiet year, Path B saves about $2,600. In a year with surgery, Path B could cost up to about $8,400 including premiums, while Path A stays near $5,100. Path A buys predictability; Path B bets on staying healthy.
Income and IRMAA
Higher-income beneficiaries pay IRMAA surcharges on Part B and Part D on both paths. Medigap premiums aren't income-adjusted. See Part B premiums and IRMAA.
Decision grid
| If you... | Often favors |
|---|---|
| travel often or live in two states | Original Medicare + Medigap |
| want predictable costs and can afford higher premiums | Medigap |
| have specific specialists or hospitals you want to keep | Medigap, unless they're in an Advantage plan's network |
| want low premiums and are comfortable with networks | Medicare Advantage |
| value bundled extras like dental or vision | Medicare Advantage |
| have chronic conditions and might want Medigap later | Consider Medigap during the one-time window |
Timing tips
- Start comparing three months before Part B begins.
- If Medigap is a possibility, decide during your six-month open enrollment window.
- Pick a Part D plan at the same time if going with Medigap, to avoid the late enrollment penalty.
- Review your choice each fall; plans change premiums, networks and formularies.
Related: Medicare enrollment timeline and health care cost inflation.
Prior authorization and how care gets approved
Original Medicare generally doesn't require prior authorization for most services, and a Medigap policy follows Medicare's coverage decisions: if Medicare pays, Medigap pays its share. Medicare Advantage plans can require prior authorization for some services, such as certain imaging, procedures or post-hospital care. Plans must cover the same basic services as Original Medicare, but the approval process is managed by the plan. If you expect significant care, read the plan's rules for referrals and authorizations as closely as the premium.
Living abroad or splitting time
Original Medicare generally doesn't cover care outside the U.S. Some Medigap plans include limited foreign travel emergency coverage. Medicare Advantage plans vary, and many offer little coverage outside their service area except for emergencies. Snowbirds who spend months in another state often find Original Medicare with Medigap simpler, since it works with any provider nationwide that accepts Medicare. See health insurance abroad.
Common misconceptions
- "$0 premium means free." You still pay Part B, plus copays when you use care.
- "Medigap covers drugs." Current Medigap plans don't; you need Part D.
- "I can buy Medigap any time." Outside guaranteed issue situations, insurers may underwrite.
- "All Advantage plans are the same." Networks, extras and cost-sharing vary widely.
FAQ
Can I have Medigap and Medicare Advantage at the same time?
No. Medigap works only with Original Medicare. If you join a Medicare Advantage plan, a Medigap policy won't pay for its cost-sharing.
When is the best time to buy Medigap?
During your six-month Medigap Open Enrollment Period, which starts the first month you have Part B and are 65 or older. Insurers generally can't use medical underwriting then.
Do Medicare Advantage plans have an out-of-pocket limit?
Yes. Each plan sets an annual in-network out-of-pocket limit. Original Medicare alone has none, which is why many people add Medigap.
Can I switch from Medicare Advantage back to Original Medicare?
Generally yes, during certain enrollment periods, but buying Medigap afterward may require medical underwriting unless you have a guaranteed issue right.
Which is cheaper, Medicare Advantage or Medigap?
Medicare Advantage often has lower premiums, while Medigap usually has lower costs when you use care. In a healthy year Advantage tends to cost less; in a year with major care, Medigap often costs less and is more predictable.
Sources & fact-check notes
- Medicare.gov: Get ready to buy (Medigap Open Enrollment) (accessed 2026-10-25)
- CMS fact sheet: 2026 Medicare Parts A & B premiums and deductibles (accessed 2026-10-25)
- Medicare.gov: When does Medicare coverage start? (accessed 2026-10-25)
Figures checked October 25, 2026. Rules and limits change; verify with the official source before acting.