Medigap Guide
Medigap (Medicare Supplement): Plan G, Plan N & Enrollment Windows
Medigap fills the cost gaps left by Original Medicare — deductibles, coinsurance, and copays. Here's how Plan G compares to Plan N, why timing your enrollment matters, and how medical underwriting works outside your window. Reviewed with Kayla Price, licensed across 10 states.
Last reviewed: July 2026
What Is Medigap?
Medigap policies are sold by private insurers and standardized by the government into lettered plans (A through N in most states) — every insurer's "Plan G," for example, covers the identical set of benefits, so the only real differences between companies are price, customer service, and financial strength. Medigap only works alongside Original Medicare, not Medicare Advantage.
Plan G vs. Plan N vs. High-Deductible Plan G
Plan G
Covers nearly everything Original Medicare doesn't, except the annual Part B deductible ($283 in 2026). Higher premium, very predictable costs.
Plan N
Lower premium than Plan G, but you pay small copays (up to $20 for some office visits, up to $50 for ER visits that don't result in admission) and any Part B excess charges.
High-Deductible Plan G
Same coverage as Plan G once you meet an annual deductible (adjusts yearly), in exchange for a much lower monthly premium — good for lower expected utilization.
Medigap Open Enrollment Period
Your Medigap Open Enrollment Period is a one-time, 6-month window that starts the month you're both 65 and enrolled in Medicare Part B. During this window, insurers must sell you any Medigap policy they offer, at the standard rate, regardless of health conditions.
Outside that window — or outside a guaranteed-issue right, such as losing other coverage involuntarily — insurers can use medical underwriting: asking health questions and potentially charging more or denying coverage based on your answers. This is the single most important timing decision in Medigap shopping.
Related Reading
- Understanding Medicare Supplement (Medigap) Plans
- The Truth About Medicare Supplement Plans
- Medicare Supplement vs. Medicare Advantage
- How to Switch Medicare Supplement Plans Outside of Open Enrollment
- Medicare Advantage vs. Medigap: Which Is Right for You?
See also our Medicare Plans overview, the Medicare Advantage Guide, the Part D Guide, and our Medicare FAQ. For a more ground-up, self-paced walkthrough of Medicare basics, our free course at LearnMedicare.org is a good complement to this guide.
Frequently Asked Questions
What is Medigap?
Medigap, or Medicare Supplement insurance, is a private insurance policy that works alongside Original Medicare to help cover out-of-pocket costs like deductibles, copays, and coinsurance.
What is the difference between Plan G and Plan N?
Plan G covers nearly all Medicare-approved out-of-pocket costs except the Part B deductible. Plan N has a lower premium but requires small copays for some doctor and ER visits, and doesn't cover Part B excess charges.
What is High-Deductible Plan G?
High-Deductible Plan G offers the same coverage as standard Plan G, but you pay a deductible (which adjusts annually) before the plan starts paying, in exchange for a significantly lower monthly premium.
When is the best time to enroll in Medigap?
Your Medigap Open Enrollment Period is the 6-month window starting the month you're both 65 or older and enrolled in Part B — during this window, insurers can't deny you coverage or charge more based on health conditions.
Can I be denied a Medigap policy?
Outside your Medigap Open Enrollment Period or a qualifying guaranteed-issue situation, insurers can use medical underwriting and may deny coverage or charge higher premiums based on your health history.
Does Medigap cover prescription drugs?
No. Medigap plans don't include prescription drug coverage — you'll need a separate Part D plan alongside your Medigap policy.
Can I switch Medigap plans later?
Yes, but outside your initial enrollment window or a guaranteed-issue right, switching typically requires medical underwriting, and the new insurer can decline you or adjust pricing based on health.
Is Medigap the same in every state?
Most states use standardized Medigap plans labeled A through N with identical benefits between insurers, though pricing varies. A few states use different rules — always confirm what's available where you live.
Local Coverage
Find Local Medicare Help Near You
Medicare plan availability and pricing vary by county. Get city-specific plan info for your area.