Medigap
Original Medicare Covers 80%. What About the Other 20%?
Medicare Supplement insurance, better known as Medigap, is built to pay the deductibles, coinsurance, and copayments Original Medicare leaves behind.
Quick Answer
Medigap is standardized supplemental insurance that pays some or all of the out-of-pocket costs Original Medicare doesn't — like deductibles, coinsurance, and copayments. Plans are labeled by letter (like Plan G or Plan N), and your best window to buy one without medical underwriting is a 6-month period around your 65th birthday.
How Medigap Fills the Gaps
Original Medicare (Parts A and B) generally covers about 80% of approved costs for the services it covers, leaving you responsible for deductibles, coinsurance, and copayments — with no annual out-of-pocket maximum. A Medigap policy is designed specifically to pick up some or all of that remaining 20%, depending on the plan letter you choose. Because Medigap plans are standardized by the federal government, the core benefits of a given plan letter, like Plan G, are identical no matter which insurance company sells it — only the premium and service tend to differ between carriers.
Plan G vs Plan N — Which Is Right for You?
| Feature | Plan G | Plan N |
|---|---|---|
| Part B coinsurance | Covered in full | Covered, except small copays for some office/ER visits |
| Part B excess charges | Covered in full | Not covered |
| Monthly premium | Generally higher | Generally lower |
| Predictability | Very few surprise costs | Small, predictable copays |
Neither plan is universally "better" — Plan G trades a higher premium for fewer surprises, while Plan N trades a lower premium for a few small, predictable copays. The right fit depends on how you weigh monthly cost against year-round predictability. For a broader look at Medigap next to Medicare Advantage, seeMedicare Advantage vs. Medigap.
The 6-Month Window You Can't Afford to Miss
Your Medigap Open Enrollment Period is a 6-month window that starts the month you're both 65 or older and enrolled in Part B. During this window, insurers must sell you any Medigap policy they offer, at the best available rate, regardless of your health history — no medical underwriting. Miss this window, and an insurer can generally use medical underwriting to charge you more, add exclusions, or deny coverage outright based on your health. See what to know about turning 65 for how this window lines up with your broader Medicare timeline.
Carriers We Work With
We work with a range of competitive carriers so you can compare rates for the same standardized plan letter, including Physicians Mutual, Wellabe, Humana, and other Medigap carriers available in your area.
This page is educational only and not a recommendation of any specific plan or carrier. Rates and carrier availability vary by state and change over time. You can review official Medigap details anytime atMedicare.gov.
Frequently Asked Questions
What does Medigap cover that Original Medicare doesn't?
Medigap covers some or all of the out-of-pocket costs left over from Original Medicare, such as Part A and Part B deductibles, coinsurance, and copayments, depending on the plan letter you choose.
What's the difference between Plan G and Plan N?
Plan G covers Part B coinsurance in full, while Plan N requires small copays for some doctor and ER visits and doesn't cover Part B excess charges. Plan N generally carries a lower monthly premium in exchange for those small out-of-pocket costs.
What is the Medigap 6-month enrollment window?
Your Medigap Open Enrollment Period is the 6 months starting the month you're both 65 or older and enrolled in Part B. During this window, insurers must sell you any Medigap policy they offer regardless of health history, without medical underwriting.
Does Medigap include prescription drug coverage?
No. Medigap plans don't include drug coverage, so most people pair a Medigap policy with a separate Part D plan.
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