What is Medigap and how does it work with Original Medicare?

The full explanation

When you use Original Medicare, you typically share the cost of care. Part A has a deductible for hospital stays. Part B usually covers 80% of approved services, leaving you responsible for the other 20% with no annual cap. Medigap, also called Medicare Supplement insurance, is designed to pick up some or all of those leftover costs.Medigap plans are standardized by the federal government and labeled with letters, like Plan G or Plan N. Every insurer selling Plan G must offer the same core benefits. What varies between companies is the monthly premium, not the coverage itself. That standardization makes it easier to compare.To have Medigap, you need to be enrolled in Original Medicare Parts A and B. You cannot use a Medigap policy with a Medicare Advantage plan. The two approaches serve different needs and are not designed to stack.The best time to buy Medigap is during your six-month open enrollment window, which starts the month you turn 65 and are enrolled in Part B. During that window, insurers cannot deny you coverage or charge you more based on health conditions. Outside that window, you may face medical underwriting in most states, meaning your health history could affect whether you qualify or what you pay.Medigap does not include prescription drug coverage, so you would still need a separate Part D plan.