Medicare supplement insurance, also known as Medigap, is a system of private health insurance plans intended to supplement the United States government’s federal health care plan (including Medicare Supplement Plan B). Medigap exists to fill in the gaps between the reimbursements provided by traditional Medicare Part A and Part B plans and the expenses incurred by patients in search of adequate coverage. Medigap typically covers some out-of-pocket costs that you would otherwise have to pay under original Medicare Parts A and B. These costs may include deductibles, co-insurance, and co-payments. Medigap can even help cover the costs of unplanned hospitalizations or medical procedures. However, the specifics of this coverage depends upon your individual plan.

There are 10 standardized types of Medigap supplement insurance. We’ll focus on Plan B. Medicare Supplement Plan B should not be confused with Medicare Part B, though the names are similar. Medicare Supplement Plan B is available to residents throughout most of the United States. it is important to note that Minnesota, Wisconsin, and Massachusetts residents may have to choose from one of their states’ own standardized Medigap plans.

What Plan B covers

Medigap Plan B includes Medicare Part B co-insurance and co-payments. Co-payments are usually tiered and feature a set amount that you must pay. For example, you might be responsible for a $40 co-payment for any service that your doctor performs from a given tier defined by Medicare. Co-insurance, on the other hand, requires you to pay a percentage. So instead of a flat $40 fee as in the case of the co-payment, you might have to pay 20% of the total cost for a given procedure or service.

Medigap Plan B also covers the first three pints of blood that you receive as a hospital inpatient or outpatient. Original Medicare typically covers any additional pints that you may need. This supplement plan also covers the Medicare Part A deductible as well as Medicare Part A hospital expenses and co-insurance for up to a year after your Medicare benefits are exhausted. Finally, Medigap Plan B covers hospice care co-payments and co-insurance under Medicare Part A.

What won’t Medigap Plan B cover? It does not cover:

  • the Medicare Part B deductible
  • any Medicare Part B excess charges
  • any skilled nursing facility care co-insurance or co-payments
  • any foreign travel emergency care

Since Medigap Plan B coverage is offered by private insurance companies instead of by the federal government, plan costs and availability can and do vary widely based on your location and the company that you choose. The federal government, however, does require Medigap providers to offer a standard set of Plan B benefits.

What Plan B costs

So how much does a Medigap Plan B costs. As mentioned, that will depend on a number of factors. Private companies set their monthly premiums based on age, health status, sex, and various other factors. Different companies may even charge different rates for the same Medigap Plan B coverage. It is in your best interest to shop around before committing to a purchase.

Once you’ve found an appropriate plan that meets your needs, you should enroll during Medigap’s Open Enrollment Period. This starts on the first day of the month when you’re age 65 or older and enrolled in Original Medicare. The enrollment period lasts for six months. During open enrollment, you’re guaranteed the ability to enroll in whatever Medigap plan you wish even if you have pre-existing health conditions. The only qualification requirements are that you are already enrolled in Original Medicare (Part A or Part B) and that you live in the Medigap plan’s service area. If you miss the six-month Open Enrollment Period, you may be denied enrollment based on your existing health conditions.

If you want to know if Medigap Plan B is right for you, we can connect you to an insurance specialist to answer your questions.

by Lindsay Malzone, Lindsay Malzone is the Medicare expert for She's been contributing to many well-known publications as an industry expert since 2017. Her passion is educating Medicare beneficiaries on all their supplemental Medicare options so they can make an informed decision on their healthcare coverage.