Medigap: What to Know About Medicare Supplement Insurance

Medicare Supplement Insurance (also called Medigap) covers the out-of-pocket health care costs you may incur with Original Medicare (parts A and B). There are 10 standardized Medigap plans with letter names (plans C, D, E, G, etc.) that are sold by private insurers, with premiums regulated by the states. What you pay in monthly premiums can depend on where you live, what coverage you get and how old you are. Medigap plans are not used with Medicare Advantage plans.

What Medigap plans cover

Medigap policies cover some of your out-of-pocket health care costs after Medicare Part A or Medicare Part B has paid its share. Medigap policies can help cover:

Part A and Part B coinsurance.
Part A and Part B copayments.

As well as:

Part A deductible All but one of the 10 standardized plans pays all or part of the Part A deductible for in-patient hospitalization ($1,408 for every 60-day benefit period).

Part B deductible As of Jan. 1 2020, Medigap plans sold to new beneficiaries aren’t allowed to cover the Part B deductible ($198 in 2020). Two of the 10 standardized plans — plans C and F — cover the Part B deductible but aren't available to new enrollees. People who are already covered by Plans C or F are able to keep their plans and take advantage of the Part B deductible coverage.

Many plans cover 80% of medically necessary emergency services outside the U.S. after you meet a $250 deductible.

What Medigap plans don’t cover

Medigap policies don’t cover:

Long-term care.
Vision care.
Dental care.
Hearing aids.
Private duty nursing.

In addition to:

Medigap policies sold after Jan. 1, 2006, aren't allowed to include prescription drug coverage. But if you have a plan bought before that date that includes prescription drug coverage, that coverage will continue. You can receive prescription drug coverage through a Medicare Part D plan.

What you’ll pay

You pay premiums for Medicare Supplement plans, and they aren't standardized. Private insurers can charge different premiums for the same plan. Premium costs may also depend on whether your insurer offers discounts for certain people such as nonsmokers or married people. And you’ll likely pay lower premiums if you join a Medicare Select policy that offers coverage for a network of providers.

You may pay higher premiums if you enroll outside the initial open enrollment period. And in some cases, insurers can raise your premiums based on your health.

Some F and G Medigap plans charge high deductibles in exchange for lower premiums (and Plan F is no longer available to new enrollees). You pay the first $2,340 of costs not paid by Medicare before the policy kicks in.

Plans that offer foreign emergency medical service coverage charge a $250 deductible for those services.

When to enroll in Medigap

Enrolling in Medicare Supplement Insurance can be tricky. You’ll pay more, or even be denied coverage, if you don’t follow the rules for enrollment carefully.

This is the six-month period that starts the first day of the month you’re 65 years old and enroll in Medicare Part B. During that time, you can buy any Medigap policy sold in your state regardless of your health status. During this six-month Medigap enrollment period, insurers must charge people with preexisting conditions the same price as they charge people in good health.

If you apply for Medigap coverage after your open enrollment period, in all but four states, insurers are allowed to use medical underwriting to deny or charge more for coverage. “This means you may pay more in premiums or be denied coverage based on preexisting conditions such as asthma, heart disease, diabetes or a pending surgery,” says Judith Stein, executive director of the Center for Medicare Advocacy.

During the annual Medicare open enrollment period, many people choose to switch their Medicare Advantage or Medicare Part D prescription drug coverage to an option that better fits their health and financial needs. In addition, some Medicare beneficiaries switch from Original Medicare to Medicare Advantage plans.

What is more complicated, however, is moving from Medicare Advantage to Original Medicare with Medicare Supplement Insurance. Because you’ll likely be past the six-month initial enrollment period, Medigap insurers can take your health status into account before issuing you a policy.

How Medigap works with other insurance

With Original Medicare: Medicare Supplement Insurance helps pay for out-of-pocket costs incurred with Original Medicare Parts A and B only.

With Medicare Advantage: Medicare Supplement Insurance doesn't work with Medicare Advantage plans. It is illegal to sell a Medigap plan to a Medicare Advantage beneficiary.

Medigap policies sold after January 2006 aren't allowed to include prescription drug coverage. If you have one of these older policies and you want to change to a Medicare Part D policy, you can drop just the prescription portion of your existing Medigap policy. Be aware that the prescription drug coverage you’ve been using must be “creditable,” meaning it pays on average at least the same amount as Medicare standard drug coverage, or you’ll have to pay the Medicare Part D penalty. This will also happen if you go 63 days without creditable prescription drug coverage, so you’ll want to sign up soon after you drop the previous coverage.

If you have group health coverage through an employer or union and you decide to stick with that coverage, you may postpone enrolling in Medicare B without paying the Part B penalty. As a result, your Medigap enrollment period will also be postponed until the first of the month that you enroll in Medicare Part B. If you sign up for Medigap during that six-month enrollment period, you will be issued a policy, regardless of your health status.

How to compare plans

Start by determining which of the various lettered plans will fit your health care needs. For a side-by-side comparison, see this page of Medicare.gov.

Medigap policies are standardized in a different way in Massachusetts, Minnesota and Wisconsin. Click on the state name to learn more about Medigap in those places.

Once you choose the type of plan you want, you’ll need to compare prices among all the insurers that offer that plan in your area. Remember, prices can vary considerably but coverage is the same for each lettered plan. This tool on Medicare.gov can help you compare prices. Your State Health Insurance Assistance Program (SHIP) or your state insurance department can also help.

Nerd tip: Be sure to contact the insurer for each policy you are considering to double-check prices and coverage availability. Information available online can be out of date quickly.