What Is Medigap?
Key Points
- Medigap is private insurance that works alongside Original Medicare to cover your cost-sharing.
- You must have Medicare Parts A and B to be eligible for a Medigap plan.
- Medigap plans are standardized — the same letter plan offers the same benefits regardless of the carrier.
Original Medicare covers a lot — but it doesn't cover everything. Medigap plans are designed to fill those gaps. Here's how they work.
What Is Medigap?
Medigap — also called Medicare Supplement insurance — is private health insurance designed to help cover the out-of-pocket costs that Original Medicare (Parts A and B) leaves behind. These costs include deductibles, coinsurance, and copayments that can add up quickly if you have significant medical needs.
Medigap plans are sold by private insurance companies, but they are federally standardized. That means if you choose a Plan G from one carrier versus another, the coverage is identical — the only difference is the monthly premium.
How Does Medigap Work?
When you receive a covered medical service, Medicare pays its portion first. Your Medigap plan then pays its share of the remaining cost — depending on which plan you have. For example, with a Plan G, Medicare pays 80% of an approved service, and Plan G pays the remaining 20%, leaving you with little to no out-of-pocket cost for covered services.
This predictability is one of the biggest advantages of Medigap. Rather than facing unexpected bills, you know in advance exactly what your costs will be each month — your premium, plus any applicable deductible depending on the plan.
What Does Medigap Not Cover?
Medigap plans do not cover prescription drugs — you'll need a standalone Part D plan for that. They also do not cover dental, vision, hearing, or long-term care. If those benefits matter to you, a Medicare Advantage plan might be worth comparing.
Medigap plans also cannot be used if you have Medicare Advantage (Part C). They are designed specifically to work alongside Original Medicare Parts A and B.
When Can I Enroll in a Medigap Plan?
Your best window to enroll is your Medigap Open Enrollment Period — the six-month window that begins the month you turn 65 and are enrolled in Part B. During this window, no insurance company can deny you coverage or charge you higher premiums due to health conditions.
Outside of this window, you may still be able to apply for a Medigap plan, but in most states the insurer can ask health questions and deny you based on your medical history. This makes timing your enrollment correctly extremely important.
Still Have Questions?
Our licensed Medicare brokers are here to help — at no cost to you.