What Is Medigap?

Medigap, also called Medicare Supplement insurance, is a type of policy sold by private insurance companies to help pay some of the out-of-pocket costs that Original Medicare does not cover. This can include deductibles, copayments, and coinsurance, depending on the plan you choose.

Medigap plans are standardized and identified by letters, such as Plan G or Plan N. A plan of a given letter offers the same core benefits no matter which company sells it, although premiums can vary. You generally use a Medigap policy alongside Original Medicare, and you can see any provider that accepts Medicare. Medigap does not include prescription drug coverage, so most people also enroll in a separate Part D plan.

The best time to buy Medigap is usually during your Medigap Open Enrollment Period, a six-month window that starts when you are 65 and enrolled in Part B, because insurers cannot deny you coverage based on health during that time. A licensed Medicare advisor can help you compare standardized plans and premiums to find a fit for your budget and needs.

After that initial window, in many states an insurer can use your health history to decide whether to offer you a Medigap policy or what to charge, so timing your purchase matters. Because premiums for the same plan letter can differ between companies, it is worth comparing prices and considering how a carrier tends to raise rates over time before you choose a policy.