Medicare Supplement plans — often called Medigap — are insurance policies that work alongside Original Medicare to cover costs that Medicare doesn't pay, such as deductibles, copayments, and coinsurance.
How Medigap Works
When you have a Medigap plan, Medicare pays its share of an approved service first, and then your Medigap plan pays its share. Depending on the plan, you may pay little or nothing out of pocket for covered services.
Medigap plans are sold by private insurance companies, but they're standardized by the federal government. This means a Plan G from one company covers the same benefits as a Plan G from another company — the only difference is the premium.
Popular Medigap Plans
- Plan G — The most comprehensive plan available to new Medicare enrollees. Covers everything except the Part B deductible.
- Plan N — Similar to Plan G but with small copays for doctor visits and ER visits. Lower premium.
- Plan A — Basic coverage; lowest premium but least comprehensive.
Medigap vs. Medicare Advantage
Medigap works with Original Medicare — meaning you can see any doctor in the country that accepts Medicare. This is a major advantage for frequent travelers or those who want maximum provider flexibility.
However, Medigap does not cover prescription drugs (you need a separate Part D plan) and typically costs more per month than a Medicare Advantage plan. It also does not include the extra benefits (dental, vision, OTC) that many Medicare Advantage plans offer.
When to Enroll in Medigap
The best time to enroll in a Medigap plan is during your 6-month Medigap Open Enrollment Period — the 6 months starting on the first day of the month you're 65 and enrolled in Part B. During this window, insurers cannot charge you more or deny coverage based on health conditions.