Medigap is health insurance that covers some out-of-pocket expenses for people with original Medicare. Another name for Medigap is Medicare supplement insurance.

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.

We may use a few terms in this piece that can be helpful to understand when selecting the best insurance plan:

  • Deductible: This is an annual amount that a person must spend out of pocket within a certain time period before an insurer starts to fund their treatments.
  • Coinsurance: This is a percentage of a treatment cost that a person will need to self-fund. For Medicare Part B, this comes to 20%.
  • Copayment: This is a fixed dollar amount that an insured person pays when receiving certain treatments. For Medicare, this usually applies to prescription drugs.
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Medicare is federal healthcare insurance for people aged 65 years and older in the United States. Younger people with certain conditions may also be eligible to enroll.

The program has four parts:

  • Part A is hospital insurance.
  • Part B provides medical coverage.
  • Part C is an alternative to original Medicare (Part A and Part B) and is known as Medicare Advantage.
  • Part D is insurance for prescription drug costs.

Medigap is Medicare health insurance that helps cover some of the gaps in healthcare costs that original Medicare does not cover. These costs include deductibles, copays, and coinsurance. However, since January 1, 2020, Medigap has not covered the Part B deductible.

About one-third of original Medicare enrollees had a Medigap policy in 2018, according to America’s Health Insurance Plans (AHIP), a national trade association of health insurance companies.

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, including:

While some Medigap plans offer additional health insurance coverage for certain items, such as travel outside the U.S., 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, and how many of them, to offer.

All Medigap plans are standardized using a system that letters them as Plan A, B, C, D, F, G, K, L, M, or 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 the age of a person when they get the policy. This structure is called attained-age pricing, and the premiums may increase as a person gets older.

A person becomes eligible during their open enrollment period when they first qualify to enroll in Medicare Part B. During those 6 months, a person can get a Medigap policy even if they have a preexisting health condition.

If a person does not enroll during their 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, which means that the company cannot cancel the policy as long as a person continues to pay their premium.

AHIP note that from 2015 to 2018, Plan F was the most popular type of Medigap plan, accounting for at least 53% of enrollment each year. Plan G was the second most popular during that period, accounting for 17% of enrollment by 2018. Enrollment in Plan G grew 39% from 2017 to 2018.

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 this 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 set their premiums. For instance:

  • 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, although coverage may vary among plans.


All Medigap plans generally cover coinsurance costs when a person is hospitalized, including:

  • $371 per day coinsurance, which Medicare charges in 2021 for days 61–90 of a hospital stay
  • $742 per day in 2021 after 90 days
  • hospital costs for 365 days in 2021 after someone has used up their Medicare Part A hospital benefits

Medicare Part A also covers a stay of up to 100 days in a skilled nursing facility, charging $185.50 per day in coinsurance for days 21–100. Medigap plans vary in their coverage of skilled nursing facility coinsurance:

  • 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, although Medigap plans vary in their coverage of Part B 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.


Medicare Part A charges a $1,484 deductible 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 half of the deductible.
  • Plan L covers 75% of the deductible.

This online Medicare chart provides a comparison of Medigap plan coverage.

The costs vary among Medigap plans, ranging from less than $100 per month to several hundred dollars. 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

Example costs

Although Medigap K and L plans do not fully cover coinsurance costs, the plans include a cap on out-of-pocket expenses. In 2021, the out-of-pocket limits are $6,220 for Plan K and $3,110 for Plan L.

In some states, insurance companies may offer a high deductible version of Plan F or Plan G. For 2021, the deductible will be $2,370.

The New York State Department of Financial Services reported the following range of Medigap monthly premium costs in 2021 for a person in areas of Buffalo where the zip codes begin with 140–43 and 147. The plans are community-rated, meaning that the premiums are not based on age.

  • Plan A: $136.50 to $264.90
  • Plan B: $182.00 to $406.68
  • Plan C: $215.00 to $407.13
  • Plan D: $183.80 to $400.05
  • Plan F: $216.00 to $481.07
  • Plan F (high deductible): $52.53 to $95.98
  • Plan G: $183.39 to $412.33
  • Plan G (high deductible): $52.53 to $63.93
  • Plan K: $63.75 to $143.15
  • Plan L: $132.25 to $204.17
  • Plan M: $181.00 to $417.67
  • Plan N: $155.00 to $269.89

The Medigap plan finder online tool can help people compare the costs and coverage of different Medigap plans where they live.

Medigap policies may reduce out-of-pocket expenses for a person enrolled in original Medicare. However, there are several factors to consider before choosing a plan. People can find a policy that works for them by researching plans and comparing costs from different companies.