Medigap, or Medicare supplement insurance, is health insurance that covers some out-of-pocket expenses for people with Original Medicare. These can include deductibles, coinsurance, and copays.

Medigap is available in a range of plans, which vary in their coverage levels and costs.

This article discusses the different types of Medigap plans and how they work with Medicare. It also looks at enrollment and costs.

Glossary of Medicare terms

  • Out-of-pocket cost: This is the amount a person must pay for care when Medicare does not pay the total amount or offer coverage. Costs can include deductibles, coinsurance, copayments, and premiums.
  • Premium: This is the amount of money someone pays each month for Medicare coverage.
  • Deductible: This is an annual amount a person must spend out of pocket within a certain period before Medicare starts to fund their treatments.
  • Coinsurance: This is the percentage of treatment costs that a person must self-fund. For Medicare Part B, coinsurance is 20%.
  • Copayment: This is a fixed dollar amount a person with insurance pays when receiving certain treatments. For Medicare, this usually applies to prescription drugs.

Medigap is supplemental health insurance that helps cover some of the gaps in healthcare costs that Original Medicare (parts A and B) does not cover.

These costs include deductibles, copays, and coinsurance. However, since January 1, 2020, Medigap has not covered the Part B deductible.

About 42% of people with Medicare also had Medigap in 2022, according to the most recent information from the Kaiser Family Foundation (KFF).

There are 10 different Medigap policies, which are only available to a person enrolled in Original Medicare. They do not cover out-of-pocket costs of other types of health insurance, such as:

While some Medigap plans offer additional health insurance coverage for certain items, such as travel outside the United States, the policies do not generally cover the following expenses:

  • vision care, including eyeglasses
  • dental care
  • hearing aids
  • long-term care, such as nursing homes
  • private-duty nursing

Private insurance companies offer Medigap plans. Each provider can choose which plans they offer.

All Medigap plans are standardized using a system of letters: A, B, C, D, F, G, K, L, M, and N. Plans with the same letter provide the same benefits. For example, Plan N from one company will offer the same coverage as Plan N from a different company, even across different states.

Despite this standardization, a person may wish to consider the following factors when selecting a plan:

  • Three states — Massachusetts, Minnesota, and Wisconsin — have their own systems for categorizing Medigap plans.
  • Companies in some states offer Medigap policies known as Medicare SELECT. The plans use the same lettering system as other Medigap policies, but an enrollee must use hospitals or healthcare providers within the plan’s network. Medicare SELECT plans may cost less than Medigap plans with the same letter.
  • A company may base the plan premiums on a person’s age when they get the policy. This structure is called attained-age pricing, and the premiums may increase as a person ages.

A person becomes eligible for Medigap during the 6-month open enrollment period when they first have Medicare Part B. During this time, a person can get a Medigap policy even if they have a preexisting health condition.

If a person does not enroll during the Medigap open enrollment period, a Medigap provider may choose to refuse coverage on the basis of a person’s preexisting condition or charge higher premiums.

However, all Medigap plans have “guaranteed renewable” status as long as a person pays their premium. This means that the company cannot cancel the policy as long as a person continues to pay their premium.

Factors to consider

Coverage through a Medigap plan is for individuals only, which means that married individuals must have separate policies.

A person can find out which companies offer Medigap plans in their area using the online search tool or by seeking information from the State Health Insurance Assistance Programs network. They may wish to consider the following points when comparing Medigap plans:

  • which benefits are most important, considering present and future health needs
  • which Medigap plans provide the preferred benefits
  • the costs of Medigap policies from different companies

Another consideration is how the company sets its premiums. This can include the following points:

  • Community-rated premiums are not based on age, although the costs may increase due to inflation.
  • Issue age-rated premiums are based on a person’s age when they get the policy, and the costs do not increase as a person gets older.
  • Attained age-rated premiums are based on a person’s age when they get the policy, with the costs increasing as they get older.

Medigap helps cover gaps in healthcare costs, such as deductibles, copays, and coinsurance. Coverage may vary among plans.

Coinsurance

All Medigap plans generally cover Part A coinsurance costs when a person is hospitalized/

Some plans may also cover a stay in a skilled nursing facility:

  • Plans A and B do not provide coverage.
  • Plans C, D, F, G, M, and N provide full coverage.
  • Plan K provides 50% coverage.
  • Plan L provides 75% coverage.

Medicare Part B covers outpatient care, and a person usually pays 20% coinsurance after meeting their deductible. Medigap plans vary in their coverage to help with the cost of the coinsurance:

  • Plans A, B, C, D, F, G, M, and N generally cover Part B coinsurance.
  • Plan K provides 50% coverage.
  • Plan L provides 75% coverage.

Deductible

Medicare Part A charges adeductible each time a person stays in the hospital, but Medigap plans vary in their coverage of the deductible:

  • Medigap Plan A does not cover the deductible.
  • Plans B, C, D, F, G, and N fully cover the deductible.
  • Plans K and M cover 50% of the deductible.
  • Plan L covers 75% of the deductible.

Learn more about comparing Medigap plans.

The costs vary among Medigap plans. Several factors contribute to these cost differences:

  • the plan provider’s policies
  • the person’s age when they enroll in a Medigap plan
  • the chosen plan
  • the person’s location

A person can enter their ZIP code on the Medicare website to find Medigap plans in their area and compare costs.

Learn more about the costs of Medigap.

Medigap policies may reduce out-of-pocket expenses for a person enrolled in Original Medicare (parts A and B). This can include help with the costs of deductibles, coinsurance, and copays.

Different Medigap plans offer different coverage. A person can find a policy that works for them by researching plans and comparing costs from different companies.