Updated June 17, 2026
Medigap and Medicare Advantage are not the same thing and cannot be combined. Medigap works alongside Original Medicare (Parts A and B) to cover cost-sharing such as deductibles and coinsurance, while Medicare Advantage replaces Original Medicare with a private plan that often bundles extra benefits. Your choice will determine which doctors you can see, what you pay out of pocket, and how your coverage travels with you.
What Is Medigap?
Medigap is private health insurance sold by state-licensed insurers to fill the cost-sharing gaps that Original Medicare leaves behind. Plans are standardized by the federal government, meaning a Plan G from one insurer must offer the same core benefits as Plan G from any other insurer. You can learn about all standardized plan types at Medicare.gov's Medigap plan comparison tool.
Key features of Medigap:
- Works with any doctor or hospital that accepts Medicare nationwide, with no network restrictions.
- Covers cost-sharing such as the Part A hospital deductible, Part B coinsurance, and (with most plans) excess charges.
- Requires you to keep paying your Part B premium in addition to the Medigap premium.
- Does not include prescription drug coverage; you must enroll in a standalone Part D plan.
- Generally has higher monthly premiums but more predictable out-of-pocket costs.
What Is Medicare Advantage?
Medicare Advantage (Part C) is an alternative way to receive your Medicare benefits through a private insurer approved by the Centers for Medicare and Medicaid Services (CMS). You can review plan availability and star ratings at Medicare.gov.
Key features of Medicare Advantage:
- Often includes HMO or PPO networks that restrict which providers you can use at in-network rates.
- Frequently bundles Part D drug coverage, dental, vision, and hearing benefits.
- Typically has lower monthly premiums than Medigap but higher potential out-of-pocket exposure (annual maximums can reach several thousand dollars).
- Coverage does not travel as freely; out-of-area care is often limited to emergencies.
- Plans can change benefits, premiums, and formularies each year.
Side-by-Side Comparison
| Feature | Medigap | Medicare Advantage |
|---|---|---|
| Works with Original Medicare | Yes | No (replaces it) |
| Provider network | Any Medicare-accepting provider | Usually network-restricted |
| Monthly premium | Higher | Often lower (or $0) |
| Out-of-pocket predictability | High (most cost-sharing covered) | Variable (annual OOP max applies) |
| Prescription drugs | Separate Part D plan needed | Usually bundled |
| Extra benefits (dental, vision) | Rarely | Commonly included |
| Travel coverage | Nationwide | Emergency only (in most plans) |
| Annual plan changes | Benefits stable (premiums may rise) | Benefits and formularies can change yearly |
Who Typically Benefits from Medigap?
Medigap tends to suit people who:
- Travel frequently or divide time between states and want nationwide provider access.
- Have ongoing or complex medical conditions and value predictable out-of-pocket costs.
- Prefer to see any Medicare-participating specialist without a referral (depending on plan type).
- Can afford a higher monthly premium in exchange for minimal surprise bills.
Who Typically Benefits from Medicare Advantage?
Medicare Advantage may be a good fit for people who:
- Are generally healthy and want to minimize monthly premium spending.
- Live in one area year-round and are comfortable with a local provider network.
- Value bundled benefits like dental and vision in a single plan.
- Are comfortable reviewing their plan each Annual Enrollment Period (October 15 through December 7) to ensure continued fit.
Switching Between the Two
One critical timing fact: if you enroll in Medicare Advantage first and later want to switch to Medigap, you may face medical underwriting in most states. Insurers can review your health history and decline to cover you or charge higher premiums outside of guaranteed-issue situations. This is different from your initial Medigap Open Enrollment Period, the six-month window that begins the month you turn 65 and are enrolled in Part B, during which insurers must sell you any plan at standard rates regardless of health. You can estimate your costs using the Medigap cost calculator before you commit.
How to Verify and Get Help
Medicare rules are detailed and subject to change. Always verify plan specifics at Medicare.gov and consider speaking with a State Health Insurance Assistance Program (SHIP) counselor, who provides free, unbiased guidance. CMS publishes enrollment and coverage data at CMS.gov.
Cost Structures: Premiums, Deductibles, and Out-of-Pocket Maximums
One of the sharpest differences between Medigap and Medicare Advantage is how costs are structured over the year. With Medigap, you pay a predictable monthly premium. In return, the plan covers most or all of Medicare's cost-sharing, so your bills after receiving care are minimal or zero depending on the plan you choose. This makes annual health spending highly predictable, which many people on fixed incomes find valuable.
With Medicare Advantage, you may pay a lower or $0 monthly premium, but the plan imposes copays, coinsurance, and deductibles each time you use services. Every Medicare Advantage plan must cap your annual out-of-pocket spending at a federally set maximum (which in 2025 can be as high as $9,350 for in-network services). If you need significant care in a given year, you could reach that cap. Understanding that ceiling is essential when comparing the two approaches.
Prescription Drug Coverage
Medigap plans do not include prescription drug coverage. If you choose Medigap, you must also enroll in a separate Medicare Part D prescription drug plan to cover your medications. Part D plans are sold by private insurers and vary in formulary (the list of covered drugs), premiums, and pharmacy networks.
Most Medicare Advantage plans bundle Part D drug coverage into the plan itself, which can simplify things. However, if a Medicare Advantage plan's formulary does not cover your medications well, you may face high drug costs even if the plan's premium looks attractive. Always check whether your specific medications are covered on a plan's formulary before enrolling.
Stability and Annual Changes
Medigap benefits are standardized by federal law and do not change from year to year (although premiums can increase). A Plan G purchased today will offer the same core benefits in 10 years. Medicare Advantage plans, by contrast, can change their benefits, premiums, copays, provider networks, and drug formularies each January 1. You receive an Annual Notice of Change each fall and must review it to understand what your plan will look like the following year. If the changes are unfavorable, you can switch during the Annual Enrollment Period (October 15 through December 7).
For people who dislike re-evaluating their health coverage every year or who have complex medical needs that require stable, broad access to providers, Medigap's consistency is a meaningful advantage. For people who are engaged health care consumers and comfortable with annual plan reviews, Medicare Advantage's flexibility and additional benefits can be a good trade-off.
Related reading
- Plan G covers nearly all Medicare cost-sharing. Plan N costs less per month but adds copays and exposes you to Part B excess charges. Here is how to compare them.
- Your best window to buy Medigap is the 6-month Open Enrollment Period starting when you turn 65 and enroll in Part B. After that, medical underwriting usually applies.