A Medicare Supplement, commonly called Medigap, is private health insurance that fills coverage gaps in Original Medicare — such as Part A and Part B deductibles, coinsurance, and copayments. Medigap does not replace Medicare; it works alongside it to reduce your out-of-pocket costs.
ClearValue Lending is not affiliated with, endorsed by, or connected to Medicare, CMS, or any government agency. This page is general financial education, not insurance advice. This page does not market, compare, or rank specific Medigap plans or insurance companies. For coverage options specific to your situation, visit Medicare.gov, call 1-800-MEDICARE (1-800-633-4227), or contact your free SHIP counselor at shiphelp.org.
Original Medicare (Parts A and B) requires cost-sharing — deductibles, coinsurance, and copayments — that can add up significantly, especially with a serious illness. A Medigap policy is private insurance sold by insurance companies approved by your state that pays some or all of those costs after Medicare has paid its share. Medigap policies are standardized by federal and state law, meaning Plan G from any insurer must offer the same core benefits as Plan G from any other insurer in most states. Medicare.gov's Medigap overview is the authoritative educational resource.
Medigap plans are lettered (A, B, D, G, K, L, M, N in most states; Plans C and F are closed to those new to Medicare after January 1, 2020). The benefits vary by plan letter. Common Medigap benefits include Part A hospital coinsurance, Part A hospice care coinsurance, Part B coinsurance or copayments, and for some plans the Part A and/or Part B deductibles. Plans C, D, F, G, M, and N also include a foreign travel emergency benefit (usually 80% of covered emergency care outside the U.S. after a deductible, up to a lifetime maximum).
What Medigap does NOT cover: prescription drugs (you must have a separate Part D plan), dental, vision, hearing, long-term care, or private-duty nursing. It also does not work with Medicare Advantage plans — you can have Medigap only with Original Medicare.
Your best window to buy a Medigap policy is during your Medigap Open Enrollment Period: a one-time 6-month window that starts the month you turn 65 AND are enrolled in Medicare Part B. During this window, an insurer cannot deny you coverage or charge you more based on your health status (pre-existing conditions). Outside this window, insurers in most states can use medical underwriting — they can charge more or deny coverage based on your health. This is a key reason why buying during the open enrollment window often results in better access and pricing. Medicare.gov's Medigap enrollment guide explains the timing in detail.
These are two fundamentally different ways to manage Medicare costs. Medigap supplements Original Medicare — you keep Parts A and B and your Medigap policy covers your out-of-pocket share. Medicare Advantage replaces Original Medicare with a private plan that bundles Parts A, B, and usually D. You cannot hold a Medigap policy and a Medicare Advantage plan at the same time. The right choice depends on factors such as your expected health utilization, preferred providers, and how important predictable costs vs. lower premiums are to you. For a neutral comparison of options, the free SHIP counseling service (shiphelp.org) provides guidance without selling anything.