Medicare Supplement FAQ

Medicare Supplement Insurance, also known as Medigap, helps fill the coverage gaps found in Original Medicare (Parts A and B). Typically, Medicare covers around 80 percent of enrollees’ medical expense. That other 20 percent may add up to significant costs for some beneficiaries, particularly if they have chronic conditions. This Medicare Supplement FAQ answers beneficiaries’ most common Medigap questions.

What Is Medicare Supplement Insurance?

Private insurers offer Medigap policies to help cover the costs not covered by Original Medicare, such as co-insurance, co-pays, and deductibles. In addition, some supplemental policies may cover services not covered by Medicare Parts A and B, such as healthcare coverage for overseas travel.

Note that Medigap is not the same thing as Medicare Advantage, even though both are provided by private insurers.

What Does Medicare Supplement Insurance Cover?

There are 10 different Medigap plans offered in most states. The plans correspond with a letter – A, B, C, D, F, G, K, L, M, and N. Plan F also offers a high deductible plan.

Insurers who offer Medigap policies must offer Plan A. They may offer only Plan A but, if they choose to offer additional plans, they must also offer either Plan C or Plan F. All plans are standard, meaning that benefits remain essentially the same across all 50 states. However, not all policies are available in every state. Some states provide Medicare SELECT, which may be any standardized Medicare Supplement plan but often requires beneficiaries to receive care from within a provider network.

If you currently have plans F, E, H, I, or J, you may keep your plan, even though these are no longer available for new beneficiaries.

Medigap plans help cover the costs of Medicare Parts A and B. Actual coverage amounts, i.e. percentage of costs covered, vary from plan to plan. provides a chart comparing Medigap plans and which costs each plan covers.

When Can I Apply for Medicare Supplement Insurance?

You may apply for a Medigap plan during the following windows:

  • Open enrollment
  • During the six months following your enrollment in Medicare Part B (if you are aged 65 or older)
  • For six months after turning 65 if you became eligible for Part B before turning 65

If you become eligible before age 65 due to permanent kidney failure (ESRD), amyotrophic lateral sclerosis (ALS), or disability, Medicare guarantees the supplement policy of your choice during the first six months after you turn 65 and have enrolled in Part B.

Does Medicare Supplement Coverage Include Prescription Drug Benefits?

No. Medicare Part D provides prescription drug coverage. Medigap plans cover the gaps left by Medicare Parts A and B.

Who Is Eligible for Medicare Supplement Insurance?

If enrolled in Original Medicare, you are eligible for Medicare Supplement coverage. During your six-month open enrollment period, you may enroll in any Medigap plan you choose, without regard to your medical history. Outside of that window, providers may apply medical underwriting to your application.

If you have Medicare but are not 65 (due to ESRD, ALS, or disability), some states allow you to purchase Medigap coverage, although you may pay additional premiums.

Can You Have Medicare Supplement Insurance with Medicare Advantage?

No, you cannot use a Medigap policy to cover Medicare Part C (Medicare Advantage) costs. If you already have a Medicare Advantage plan, it is illegal for any insurer to sell you a Medigap policy unless you are switching to Original Medicare.

If you already have a Medigap policy when you change to Medicare Advantage, you may drop your Medigap policy. However, you may not be able to acquire another Medigap policy if you later return to Original Medicare. You may also not be able to get the same plan you had previously.

If this is your first time with a Medicare Advantage plan, you may get the same policy (if the insurer still offers it) if you switch to Original Medicare within 12 months. Alternatively, you may purchase a different Medigap policy.

Is There a Best Time to Sign Up for Medicare Supplement Insurance?

The ideal time to enroll in a Medigap plan is during the open enrollment period, the six-month window following your initial enrollment in Medicare Part B. This is because private insurers may not refuse you a policy or base your premium on your medical history. In addition, they cannot make you wait for coverage to take effect unless you have a preexisting condition diagnosed and/or treated during the six months before your supplemental coverage would have begun.

Special Enrollment Periods include:

  • Leaving a Medicare Advantage Plan during your 12-month trial right
  • Leaving a plan because it doesn’t adhere to Medicare rules and guidelines
  • Losing a secondary plan
  • Moving out of your service area
  • Your current Medigap or Medicare Advantage plan leaves Medicare or ends coverage in your area

If you wait until after open enrollment, insurers medically underwrite your application, which may lead to a higher premium or the complete decline of coverage.

What Is the Cost of Medicare Supplement Insurance?

Medigap policies vary as to cost, depending on insurer, coverage options, location, and more. When comparing plans, look at coverage offered by the same plans (i.e. Plan C to Plan C) to be sure you compare apples to apples. Some things to remember include:

  • Some insurers offer discounts, so look at potential discounts and whether you qualify
  • Medicare SELECT policies often charge lower premiums due to the network requirements
  • The high-deductible Medigap Plan F requires beneficiaries to pay $2,340 out of pocket before Medigap pays anything (as of 2020)

Will I Have Medicare Supplement Insurance Outside of the U.S.?

It depends on your plan. In 2020, Medigap plans C, D, F, G, M, and N offer emergency healthcare coverage for international travel. If you purchased plans E, H, I, or J before June 1, 2010 and still have this plan, you also have international coverage. All of these plans include emergency care that occurs during the first 60 days of your tip that Medicare otherwise wouldn’t cover, paying 80 percent of the costs once you meet a $250 annual deductible. The lifetime limit is $50,000. Verify coverage with your provider before traveling.