Medicare Supplemental Insurance, also known as Medigap, works with Original Medicare to pay for the out-of-pocket portion you would otherwise be expected to pay for healthcare services. There are currently 10 different supplemental insurance plans available. All are designated by a letter. The most common ones are Plans F, G, or N. Medicare has standardized the plans, meaning that all plans of the same letter must offer the same basic benefits no matter which insurance company is selling you the plan.

The cost of the plan may vary from state to state, but the benefits for each plan letter will be the same. This is true for all states except for Massachusetts, Minnesota, and Wisconsin. These states each have their own Medigap plan standards.

When is the Best Time to Enroll in a Medigap Plan?

The best time to enroll in a Medigap Plan is during your Initial Enrollment Period when you first become eligible for Original Medicare. You will have “guarantee issue” for a Medigap Plan, which means the Medigap Plan you select may issue you the policy without conducting any medical underwriting. You may not be denied coverage even if you have a pre-existing condition.

After your Initial Enrollment Period, you can add a Medigap Plan later during the annual enrollment period from October 15 to December 7. But you may be subjected to medical underwriting which means you might be denied coverage or be charged a higher monthly premium due to a pre-existing condition.

There are a few exceptions to this rule. For example, if you move and the company does not provide coverage in your new location, you may be able to choose a new Medigap Plan that is guarantee issue. Some states allow you to change Medigap Plans during your birthday month, but generally, they may allow you to change to a policy that offers lower benefits, but not greater ones.

Before making any decisions, you may need to evaluate each plan letter to determine which Medigap policy best meets your needs. For more information visit Medicare Supplement (Medigap) Enrollment.

Understanding the Basics About Medigap Plans

There is some general information about Medigap Plans you need to know.

  • You must have Part A and Part B of Original Medicare to be eligible to purchase a Medigap policy.
  • As mentioned earlier, the best time for you to purchase a Medigap policy is during your Initial Enrollment Period which begins the month you turn 65 and continues for six months. During this time, you may have guarantee issue of the policy, which means the insurance company may sell you the policy even if you have health problems and a pre-existing condition. After that initial period, you will be subject to medical underwriting and an insurance company may refuse to sell you a Medigap policy. There are some exceptions to this, and some states have different requirements.
  • A Medigap policy does not provide you additional benefits but pays for some of your approved costs for Part A and Part B services. Medigap plans do not include prescription drug costs. You must join a Drug Plan (Part D) to have coverage for your prescription drugs.
  • A Medigap plan pays its share of costs after your Original Medicare pays its share.
  • If you have a Medicare Advantage Plan, you cannot also have a Medigap plan.

Important Definitions to Know When Comparing Plans

To understand the different types of coverage offered by each plan, you need to know three terms.

  • Coinsurance: This is the amount you pay after you have met your deductible. Generally, for most services provided under Original Medicare Part B, you will pay 20% and Medicare will pay 80%.
  • Copay: A copay is a fixed amount you pay for a covered medical service.
  • Deductible: This is the amount you must pay out-of-pocket before your Medigap Plan will kick in. For 2022, the deductible is $1,556 for each Part A benefit period and $233 for each Part B benefit period.

Comparing Plans: What is Covered Under Medigap Plan F?

Plan F has been by far the most popular Medigap Plan and is known as the “Cadillac Plan.” It pays almost all the most common costs you would otherwise have to pay for out-of-pocket.

Unfortunately, Plan F is being phased out. You are only eligible for this plan if you enrolled in Original Medicare before January 1, 2020. If you became eligible for Original Medicare after that date, you cannot enroll in a Plan F.

If you are eligible and purchase a Plan F, it may pay for the following out-of-pocket costs:

  • Part A coinsurance after Original Medicare Part A benefits have been used up.
  • Part A deductible.
  • Parts A and B coinsurance and copayments.
  • Part B deductible.
  • Part B excess charges.
  • The first three pints of blood that are used for any approved procedure.
  • Coinsurance for a skilled nursing facility.
  • Coverage for emergency care (pays 80%) outside of the U.S. up to the plan limit amount.
  • Hospice care coinsurance.

This is the most expensive of all Medigap plans, but it provides more coverage than any other plan. You may choose a higher deductible which will lower the cost of your monthly premium. For more information visit Medicare Supplement Plan F.

Comparing Plans: What is Covered Under Medigap Part G?

Plan G is the next most popular plan after Plan F and is essentially the “New Cadillac Plan” when you compare Medigap Plan F vs G. It is particularly attractive for those who are ineligible for Plan F, which are those who only became eligible for Original Medicare after January 1, 2020. Medigap Plan G provides:

  • The same coverage as Plan F except that it does not cover the Plan B deductible. Plan G covers all Part A deductibles, coinsurance, and copays.
  • The Part B deductible for 2022 is $233. You must pay this amount. There is no Medigap Plan that pays for the Part B deductible.
  • Like Medigap Plan F, Medigap Plan G will pay for Part B excess charges. This means that if you see a provider who does not participate in Original Medicare, the provider may charge you up to 15% more than what the standard Medicare rate is for a particular service.
  • If you have Plan F or Plan G, those excess charges will be covered. No other Medigap Plan covers excess charges. This will be important to you if provider choice is important, and you want the flexibility to seek medical services from a provider who does not participate in Medicare.

There are currently no plans to phase out Medigap Plan G policies.

Comparing Plans: What is Covered Under Medigap Plan N?

Medigap Plan N is less expensive than Plans F or Plan G. It is very similar to Plan G EXCEPT, when comparing Medigap Plan N vs G, be aware of the following:

  • There is no coverage for the Original Medicare Part B deductible.
  • There is no coverage for Original Medicare Part B excess charges.
  • You will still have a co-pay of up to $20 for a doctor’s office visit.
  • You will still have a co-pay of $50 for a hospital or emergency room visit that doesn’t result in an admission.


  1. Find a Medigap Policy, Medicare.
  2. Coinsurance with High Costs, HealthCare.