What Is Medicare Supplement Insurance (Medigap) and How Does It Work?

Medigap plans help pay for certain out-of-pocket costs associated with Original Medicare.
Alex Rosenberg
By Alex Rosenberg 
Updated
Edited by Holly Carey
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Nerdy takeaways
  • Medicare Supplement Insurance is also known as Medigap.

  • Medigap plans are optional purchases to cover out-of-pocket costs for Medicare Part A and/or Part B.

  • In most states, there are 10 letter-named Medicare Supplement Insurance plan types with standardized benefits.

  • The advantage of Medigap is predictable coverage and costs. Pricey premiums can be a disadvantage.

  • You can't have Medigap with Medicare Advantage — only with Original Medicare.

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Medicare Supplement Insurance, or Medigap, is private health insurance that covers “gaps” in Original Medicare coverage. After Medicare pays for its share of covered services, Medigap covers certain out-of-pocket costs, such as copayments, coinsurance and deductibles, which you'd otherwise have to pay on your own.

In most states, there are 10 government-standardized Medigap plan types. The plans differ in terms of coverage, premiums and cost-sharing requirements.

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

Still deciding on the right carrier? Compare Medigap plans

What is Medigap and how does it work?

Medicare Supplement Insurance is extra coverage available from private insurance companies to help pay for copays, coinsurance and deductibles. A Medigap policy can cover some or all of these costs for which you’re responsible if you have Medicare Part A and Part B

Centers for Medicare & Medicaid Services. Costs. Accessed May 30, 2024.
:

  • Part A deductible: $1,632 in 2024 for each benefit period.

  • Part A inpatient hospital stay coinsurance after day 60: Starting at $408 per day in 2024. (The cost increases after day 90.)

  • Part A skilled nursing facility coinsurance after day 20: up to $204 per day in 2024. (You’re responsible for all costs after day 100.)

  • Part A hospice care coinsurance and copayments: Up to 5% of the Medicare-approved amount for respite care and up to $5 for each prescription drug.

  • Part B deductible: $240 in 2024. (Note: Since 2020, new Medicare members can’t buy any plan that covers the Part B deductible, although existing members may own older plans that do.)

  • Part B coinsurance: After the Part B deductible, up to 20% of the Medicare-approved amount for most services and durable medical equipment.

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

Without a Medicare Supplement Insurance policy, you're liable for all of those expenses out of pocket.

Medicare Supplement Insurance can be a useful means to manage your health care costs if you have Original Medicare. (Medigap plans don’t work with Medicare Advantage.) Consider your finances, expected health care expenses, risk tolerance and the Medigap plans available where you live to decide whether Medicare Supplement Insurance is right for you.

🤓Nerdy Tip

Medicare Supplement Insurance is often called Medigap, but it’s not uncommon to see it shortened to “Med Supp,” especially in government resources.

What do Medigap plans cover?

Medicare Supplement Insurance plans cover certain out-of-pocket health care costs after Medicare Part A or Medicare Part B has paid its share.

Here’s what’s covered by Medigap Plan G, the most comprehensive Medicare Supplement Insurance available to new Medicare members, according to Medicare.gov

Centers for Medicare & Medicaid Services. Compare Medigap Plan Benefits. Accessed May 30, 2024.
:

  • 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.

There are 10 standardized Medigap plans with varying levels of coverage and cost-sharing, but only eight of the 10 plans are available for purchase by new Medicare members.

(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.)

Plan G and Plan N are the most popular universally available Medicare Supplement Insurance plans. Plan G is the most comprehensive option for new Medicare members. Plan N covers nearly as much as Plan G with lower premiums, but has copays for certain medical visits.

Here are all 10 standardized plans:

Get details on Medicare Supplement Insurance options

Coverage

Medigap Plan

Basic benefits

Basics plus some extras

Highest coverage

Lower premiums, but higher copays

Lowest premiums — partial coverage

No longer for sale to new Medicare members

(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.)

Is there a Medicare Supplement plan that covers everything?

Medigap Plan F covers the most of any Medigap plan, but it’s not available for people who became eligible for Medicare after 2020. 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

Centers for Medicare & Medicaid Services. Learn What Medigap Covers. Accessed May 30, 2024.
:

  • 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.

  • Private-duty nursing.

Shopping for Medigap plans? We have you covered.

MEDICARE SUPPLEMENT, or Medigap, is private health insurance that covers “gaps” in traditional Medicare coverage. Compare options from our Medigap roundup.

Best for Medigap plan options

Best for member satisfaction

Best for premium discounts

Best for extra benefits

Medigap Plan F is the most popular Medigap plan, covering about 39% of beneficiaries in 2022

. But Plan F is losing popularity because new Medicare members can’t sign up for it. The second most popular plan, Plan G, will likely soon overtake Plan F.

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.

🤓Nerdy Tip

Medigap prices can vary significantly across health insurers and plan types — sometimes in ways that aren’t intuitive. You might even find that a high-coverage plan like Plan G has lower premiums than an option with less coverage like Plan A, so compare your quotes carefully.

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

Centers for Medicare & Medicaid Services. Choosing a Medigap Policy. Accessed May 30, 2024.
:

  • 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 before benefits kick in. (High-deductible Medigap Plan F is also available for beneficiaries who qualify for the standard version of Plan F.)

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

Centers for Medicare & Medicaid Services. Get Ready to Buy. Accessed May 30, 2024.
. The period lasts for six months, during which companies can’t factor your health or medical history into pricing or coverage decisions.

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 disadvantages 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 periods during the year when you can switch to Original Medicare with a Medigap policy: Medicare open enrollment (Oct. 15 to Dec. 7) and Medicare Advantage open enrollment (Jan. 1 to March 31)

Centers for Medicare & Medicaid Services. Joining a Plan. Accessed May 30, 2024.
.

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

Centers for Medicare & Medicaid Services. Get Ready to Buy. Accessed May 30, 2024.
:

  • 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.

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

Centers for Medicare & Medicaid Services. Choosing a Medigap Policy. Accessed May 30, 2024.
.

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 Insurance plans priced in a few ways

Centers for Medicare & Medicaid Services. Get Medigap Costs. Accessed May 30, 2024.
:

  • 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

Centers for Medicare & Medicaid Services. Choosing a Medigap Policy. Accessed May 30, 2024.
:

  • 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

Centers for Medicare & Medicaid Services. Learn How Medigap Works. Accessed May 30, 2024.
.

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.”

If you have additional questions about Medicare, visit Medicare.gov or call 800-MEDICARE (800-633-4227, TTY 877-486-2048).

Still deciding on the right carrier? Compare Medigap plans

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