Medigap and Medicare Advantage handle a major illness in very different ways, and the difference rarely shows up until you actually need care. Medicare Advantage plans cap your yearly out-of-pocket costs, but that cap can still run into the thousands of dollars, and reaching it often means working through a limited network and prior authorization requests along the way. Medigap has no such cap because, with a plan like Plan G, there’s almost nothing left for you to pay once Original Medicare processes a claim. Here’s what each option actually covers once you’re the one filling out the paperwork from a hospital bed.
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How Original Medicare Pays When You’re Seriously Ill
Both Medigap and Medicare Advantage build on top of Original Medicare (Part A and Part B), so it helps to know the baseline first. Original Medicare covers 80% of most Part B services after you meet the yearly deductible ($283 in 2026), and you’re responsible for the other 20% with no yearly limit. Hospital stays come with their own deductible ($1,736 per benefit period) and daily coinsurance that kicks in after 60 days. Source: Medicare.gov. Neither Medigap nor Medicare Advantage is required, but going without one of them means an uncapped 20% coinsurance bill if you’re hospitalized or treated for a serious condition.
How Medigap Plan G Covers You When You Get Sick
Medigap, also called Medicare Supplement insurance, is designed to close the exact gaps described above. Plan G, the most popular Medigap plan for people new to Medicare, pays your Part A hospital coinsurance (including up to 365 extra lifetime reserve days), your Part A deductible, your Part B coinsurance, skilled nursing facility coinsurance, and 80% of emergency care during foreign travel, up to plan limits. Source: Medicare.gov. The only thing Plan G doesn’t pay is the annual Part B deductible ($283 in 2026), so once that’s met, a Medigap policyholder typically pays $0 for Medicare-covered care for the rest of the year, whether that’s a same-day office visit or a month in the ICU.
💡 Tip: Medigap policies have no provider network. You can see any doctor or hospital in the country that accepts Medicare, with no referrals and no prior authorization for Medicare-covered services. Learn how Medigap works.
How Medicare Advantage Protects You When You Get Sick
Medicare Advantage takes a different approach: instead of paying your coinsurance directly, it caps what you can be charged for the year. In 2026, federal rules cap that limit at $9,250 for in-network care, or $13,900 combined if the plan covers out-of-network care at higher cost sharing (mainly PPOs). Those are the legal ceilings, not what most people actually pay: KFF’s 2026 analysis found the average enrollee’s limit is $5,421 for in-network services and $9,825 combined for plans that cover out-of-network care. Source: KFF. That cap also only applies to Part A and Part B costs; Part D drug spending has its own separate limit ($2,100 in 2026).
Getting to that capped amount isn’t always straightforward. Nearly all Medicare Advantage enrollees (99%) are in plans that require prior authorization for at least some services, most often the exact services someone uses when seriously ill: inpatient hospital stays, skilled nursing facility care, Part B drugs, and home health care. In 2024, insurers processed close to 53 million prior authorization requests and denied about 8% of them. Source: KFF. Traditional Medicare, and by extension Medigap, doesn’t generally require prior authorization at all.
Can You See Any Doctor If You Get Sick Under Each Plan?
Medicare Advantage enrollees have access, on average, to only about half (48%) of the physicians available to traditional Medicare beneficiaries in the same area, and most Medicare Advantage members are in HMOs, which typically don’t cover out-of-network care at all. Source: KFF. That’s a real tradeoff worth weighing: Medicare Advantage plans often bundle in dental, vision, and hearing benefits that Original Medicare doesn’t cover (details and limits vary by plan; see our Medicare Advantage vs Medigap comparison for how those extras stack up against Medsupp’s broader access). With Medigap, your provider options don’t narrow when you’re diagnosed with something serious. Any doctor or hospital that accepts Medicare is in-network, nationwide, for the life of the policy.
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Can You Switch From Medicare Advantage to Medigap After You Get Sick?
This is where a lot of people learn about Medigap for the first time: after a Medicare Advantage plan’s network or prior authorization rules get in the way of care they need. Switching back to Original Medicare and picking up a Medigap policy is possible through medical underwriting, where an insurance company reviews your health history before approving coverage. Some conditions are fine with certain carriers; others may lead to a decline, which is why it’s worth checking first with the Medigap Underwriting Checker before you apply.
📌 Note: A handful of situations let you switch without underwriting, including your first 12 months on Medicare Advantage (a trial right) or, in some states, an annual guaranteed-issue window. The Medigap Birthday Rule and similar state rules only apply when switching between Medigap policies; they typically don’t create a guaranteed-issue path from Medicare Advantage back to Medigap. See our state-by-state Birthday Rule guide and switching Medigap plans guide for the details that apply where you live.
Which Plan Actually Protects You Better If You Get Sick?
We here at Senior65.com believe Medigap is a superior product to most Medicare Advantage plans for most seniors who can afford it, largely because the protection doesn’t depend on which doctors are in-network or whether a claim gets approved before you get care. If a lower monthly premium matters more to you than predictable costs and open access, Medicare Advantage may still make sense. Our team can walk you through both sides for your specific health history and budget; read our full introduction to Medicare if you’re still comparing the basics.
Our help is free, and by law no one can offer you a lower price on the same Medigap plan than Senior65.com. Call 800-930-7956 to speak with a licensed agent on our team, or get a free online quote to see where you stand.