What Is Medigap (Medicare Supplement Insurance)?
Medigap, also called Medicare Supplement Insurance, is private insurance that helps pay the "gaps" in Original Medicare — deductibles, copayments, and coinsurance. Medigap plans are standardized and labeled by letter (A, B, C, D, F, G, K, L, M, N), so a Plan G from one company covers the same things as a Plan G from another; only the price and service differ. The best time to buy is your 6-month Medigap Open Enrollment Period, when you cannot be turned down or charged more for health reasons.
What does Medigap cover?
Medigap works alongside Original Medicare. After Medicare pays its share, your Medigap policy pays some or all of the remaining costs, depending on the plan letter. Most plans cover the Part A coinsurance and hospital costs, Part B coinsurance, and the first three pints of blood; more comprehensive plans also cover deductibles and skilled nursing coinsurance.
Medigap does not include prescription drug coverage — you add a separate Part D plan for that.
Why plans are labeled by letter
In most states, Medigap plans are standardized by the federal government into lettered plans. This means the benefits of each letter are identical no matter which insurance company sells it. Because the coverage is the same, the main things to compare are price, the company’s reputation, and how premiums increase over time.
The best time to buy Medigap
Your Medigap Open Enrollment Period is a one-time, 6-month window that starts the month you are 65 or older AND enrolled in Part B. During this window you have a "guaranteed issue" right: companies cannot deny you, make you wait, or charge you more because of pre-existing conditions.
After this window, in most states insurers can use medical underwriting — so buying later may cost more or be declined.
Frequently asked questions
What is the difference between Plan G and Plan N?
Both are popular comprehensive plans. Plan G covers nearly everything except the Part B deductible. Plan N also covers most costs but you pay small copays for some office and emergency-room visits and it does not cover Part B "excess charges." Plan N usually has a lower premium.
Does Medigap include drug coverage?
No. Medigap policies sold today do not include prescription drugs. You add a stand-alone Part D plan for medication coverage.
Sources
Related guides
Medicare Login Guide is an independent resource and is not affiliated with or endorsed by Medicare, the Centers for Medicare & Medicaid Services, or any government agency. This article is for general information only — confirm current figures and your specific options at medicare.gov or by calling 1-800-MEDICARE.