What Is Medigap, and What Does it Cover?

Medicare Supplement Insurance plans, also known as Medigap plans, are health insurance policies from private companies that cover “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.

Medigap plans are optional and provide secondary coverage to Original Medicare. When you receive medical care, Medicare will typically only pay a portion of your medical bills. You still have to pay deductibles, copays and coinsurance. If you buy Medigap, your Medigap plan will cover most or all of these remaining costs.

You must have Original Medicare (Part A and Part B) to buy a Medigap plan. People generally buy Medigap for more predictable coverage and fewer out-of-pocket costs. But monthly premiums may be pricey for some.

There are 10 Medigap plan types with different letter names. Medigap plans are standardized by the government, which means you get the same coverage regardless of the company that sells the plan. So, Medigap Plan G from Anthem offers the same benefits as Medigap Plan G from AARP.

You can’t have Medigap and Medicare Advantage at the same time. Medicare Advantage is a bundled alternative to Original Medicare sold by private insurers. 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]

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

Medicare Supplement plans cover certain copays, coinsurance and/or deductibles from Medicare Part A and/or Part B coverage. Medigap coverage varies by plan type. Below is a list of commonly covered benefits^[0]

Deductibles. Most Medigap plans cover part or all of your Part A deductible, which is $1,676 in 2025 for each inpatient hospital benefit period.

Coinsurance and copayments for inpatient care. Medicare Part A will cover the first 60 days of an inpatient hospital stay. After that, your copay is $419 per day in 2025 for days 61 to 90 and $838 per day in 2025 for days 91 to 150.

All Medigap plans cover these Part A copays and hospital costs up to an additional 365 days after Medicare benefits are used. Medigap plans also cover part or all of your Part A hospice care coinsurance.

Coinsurance and copayments for outpatient care. Almost all Medigap plans fully cover your Part B coinsurance, which is usually 20% of the cost of care. Plans K and L cover 50% and 75% of this coinsurance, respectively.

Other benefits. Here are a few more benefits some Medigap plans offer:

• Blood benefit: All Medigap plans come with a blood transfusion benefit that covers the first three pints of blood. (Plans K and L only cover 50% and 75%.) 

• Foreign travel benefit: Plans C, D, F, G, M and N come with foreign travel coverage. This typically pays for 80% of medically necessary emergency health care services, up to plan limits. 

• Excess charges benefit: Plans F and G also cover Part B excess charges (if a provider is permitted to charge more than Medicare’s approved amount and does so). 

Out-of-pocket limit. Unlike other Medigap plans, Plan K and Plan L cover only a portion of coinsurance and copays, so those plans come with caps on out-of-pocket spending.

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.

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

What is the best Medigap plan?

The best Medigap plan for you depends on your coverage needs and budget. If you’re looking to minimize your out-of-pocket costs, Medigap Plan G offers more coverage than any other plan available to new Medicare members. Medigap Plan G is also the most popular Medicare Supplement plan, covering about 39% of beneficiaries in 2023^[0]

The only benefit not covered by Medigap Plan G is the Part B deductible, which is $257 in 2025. Plan C and Plan F are the only Medigap plans that cover this benefit, but they’re no longer available to new members.

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 $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. Here’s what a 65-year-old female nonsmoker in Atlanta might pay per month for a few different plan types:

• Plan G: As low as $129 per month.

• High-deductible Plan G: As low as $44 per month.

• Plan K: As low as $66 per month.

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.

Other costs of Medigap

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 $2,870 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?

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.

If you don’t end up needing much medical care, you may spend more on Medigap premiums than you save on out-of-pocket costs. But it’s impossible to predict the future, and people often need more medical care as they get older. If you end up needing a lot of care, Medigap can save you thousands of dollars, even after you account for monthly premiums.

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.

Can I switch from Medicare Advantage to Medigap?

Yes. If you have Medicare Advantage, there are two open enrollment periods each year when you can switch to Original Medicare with a Medigap 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.