Medicare Supplement Insurance Plans: Coverage, Cost and FAQs

Medicare Supplement Insurance plans, or Medigap plans, are health insurance policies from private companies that cover out-of-pocket “gaps” in Original Medicare coverage. After Medicare pays its share of covered services, Medigap covers certain copays, coinsurance and deductibles you'd otherwise have to pay on your own.

Here’s what you need to know about Medicare Supplement Insurance.

What is Medigap and what does it cover?

Medicare Supplement plans cover certain copays, coinsurance and/or deductibles from Medicare Part A and/or Part B coverage. For example, here’s what’s covered by Medigap Plan G, the most comprehensive Medicare Supplement Insurance plan available to new Medicare members, according to Medicare.gov^[0]

• Part A coinsurance and hospital costs up to an additional 365 days after Medicare benefits are used up.

• Part A deductible.

• Part A hospice care coinsurance or copayment.

• Part B coinsurance or copayment.

• Part B excess charges (if a provider is permitted to charge more than Medicare’s approved amount and does so).

• Blood transfusion (first three pints).

• Skilled nursing facility care coinsurance.

• Medically necessary emergency health care service for the first 60 days when traveling outside the U.S. Deductibles and limitations apply.

Medigap plans are standardized by the government, which means you get the same Medicare coverage regardless of the company that sells the plan. So Medigap Plan G from Anthem, Mutual of Omaha or AARP offers identical Medicare benefits, for example. But companies might differ in terms of other important factors, such as premiums, discounts, customer service and/or non-Medicare perks.

What are the different types of Medicare Supplement plans?

Most states have 10 standardized Medicare Supplement plan types. The plan types vary in terms of what benefits they cover and how much they pay for medical care. High-coverage plan types generally have higher premiums, but they're also by far the most popular.

Medigap Plan G and Plan N are the most popular Medicare Supplement plan types available for any Medicare member. Plan G has the highest coverage of these options. Plan N covers nearly as much and has lower premiums, but has copays for certain medical visits.

» MORE: Medigap Plan N vs. Plan G

Here are all 10 standardized plans:

New Medicare enrollees are no longer allowed to buy plans that pay for the Medicare Part B deductible. That means if you become eligible for Medicare for the first time after Jan. 1, 2020, you can’t buy Medigap Plan C or Plan F, but the other eight plans are available.

(Massachusetts, Minnesota and Wisconsin use their own Medigap plan standards, which differ from the 10-plan standardization system used in the majority of the country.)

» MORE: Compare Medicare Supplement Insurance plan types

Is there a Medicare Supplement plan that covers everything?

Not quite. Plan F is the highest coverage Medicare Supplement plan, but you can’t buy it if you became eligible for Medicare after 2019. Plan G is the closest alternative for new Medicare members. But there are some things that aren’t covered by any Medigap plan.

What does Medigap not cover?

Medicare Supplement Insurance plans sold to new Medicare members do not cover the following^[0]

• Part B deductible. (Since 2020, new Medicare members can’t buy any plan that covers the Part B deductible, although existing members may have older plans that do.)

• Prescription drugs. (If you have Original Medicare, you can enroll in a Medicare Part D plan for prescription drug coverage. Most Medicare Advantage plans include Part D coverage.)

• Long-term care, like the non-skilled care you get in a nursing home.

• Dental care.

• Hearing aids.

• Vision care.

• Private-duty nursing.

What is the most popular Medicare Supplement plan type?

Medigap Plan F is the most popular Medicare Supplement plan, covering about 39% of beneficiaries in 2022^[0]

How much does Medicare Supplement Insurance cost?

What you’ll pay for Medigap depends on the plan type, company and factors such as your age, sex, location, tobacco use and health. Monthly premiums start as low as $30-$40, but can cost hundreds of dollars per month for older adults in higher cost areas.

In general, high-deductible plans and plans with less coverage, like Plan K and Plan L, have lower premiums. A plan with more comprehensive coverage, such as Plan G, tends to have higher premiums.

Some Medicare Supplement plans have other costs in addition to monthly premiums. Here are a few examples of other costs you might pay with certain plans^[0]

• Medigap Plan N has copays for some office and emergency room visits.

• Medigap Plan K and Plan L require you to pay out of pocket for 50% or 25% of most covered services, respectively.

• A high-deductible version of Medigap Plan G requires you to meet a deductible of $2,800 in 2024 ($2,870 in 2025) before benefits kick in. (High-deductible Medigap Plan F is also available for beneficiaries who qualify for the standard version of Plan F.)

» MORE: Are high-deductible Medigap plans worth it?

When is the best time to sign up for Medicare Supplement Insurance?

Your Medigap open enrollment period, which starts the first month you have Medicare Part B and are 65 years of age or older, is the easiest and least expensive time to enroll in a Medigap plan^[0]

After your Medigap open enrollment period ends, it never happens again, and insurers can charge more or deny coverage for a new plan due to your health status or medical history.

In some states, insurance companies sell Medigap plans to those under 65 who are living with a disability and are eligible for Medicare. You can find more information at your local State Health Insurance Assistance Program, or SHIP.

What are the disadvantages of a Medigap plan?

There are a couple of cons to consider before choosing a Medigap plan:

• Premiums: Medigap premiums can be pricey.

• Coverage: Medicare Supplement plans don’t cover everything, so you’d still have to pay out of pocket for things like dental care, vision care and long-term care.

Can I switch from Medicare Advantage to Medigap?

Yes. If you have Medicare Advantage, there are two open enrollment periods during the year when you can switch to Original Medicare with a Medicare Supplement plan: Medicare open enrollment (Oct. 15 to Dec. 7) and Medicare Advantage open enrollment (Jan. 1 to March 31)^[0]

If you're outside of your Medigap open enrollment period when you switch, you'll most likely have to go through medical underwriting. That means insurers can charge higher premiums or refuse to sell you a policy based on your health status or medical history.

There are certain circumstances when you have the right to switch without medical underwriting^[0]

• If you lose your Medicare Advantage coverage, you may have a guaranteed issue right to buy certain Medigap plans.

• If you tried Medicare Advantage and want to go back to Original Medicare with a Medigap policy within the first year, you have a trial right to switch back to certain plans.

» MORE: Medicare Advantage vs. Medicare Supplement (Medigap)

Can doctors refuse to accept Medigap insurance?

If you have a standard Medigap policy, you’re covered for any doctor who accepts Medicare. Often, your Medigap insurer will pay the provider directly, but in some cases, you might need to pay coinsurance and then get reimbursed^[0]

There’s another kind of Medigap policy that limits your provider options: Medicare Select. Medicare Select Medigap policies are typically cheaper than the standard version and they cover the same benefits. However, they can require you to use hospitals and doctors within a certain network to be fully covered for nonemergency services.

How do Medigap insurance companies set their prices?

You may see Medicare Supplement plans priced in a few ways^[0]

• Community-rated: Premiums aren’t based on age — everyone pays the same monthly premium. This kind of pricing may also be called “no age-rated.”

• Issue-age-rated: Premiums are based on the age you are when you purchase them. Generally, younger people pay lower premiums than older people. This kind of pricing may also be called “entry age-rated.”

• Attained-age-rated: Premiums are based on your current age, meaning costs will go up as you get older.

Some states require certain pricing for Medicare Supplement Insurance, so not all of the pricing methods are available in every state.

Can a Medigap policy be canceled by the insurer?

In general, your insurer can’t cancel your Medicare Supplement Insurance as long as you’re in good standing. A Medigap policy issued in 1992 or later is guaranteed renewable unless one of the following happens, according to the Centers for Medicare & Medicaid Services^[0]

• You stop paying your premiums.

• You weren’t truthful on the Medigap policy application.

• The insurance company becomes bankrupt or insolvent.

Can I have both a Medigap and a Medicare Advantage plan?

No. Medigap doesn't work with Medicare Advantage.

It's illegal for anyone to sell you a Medigap policy while you have Medicare Advantage, unless you're switching back to Original Medicare, according to Medicare.gov^[0]

What is the difference between Medicare Supplement and Medigap?

Medigap and Medicare Supplement are two interchangeable names for the same kind of insurance. Medicare Supplement Insurance can be a mouthful, so it’s often shortened to Medigap. Both terms are correct and common. You might also see it referred to as “Med Supp.”