How to Choose a Medicare Supplement (Medigap) Plan
Key takeaways:
Medicare supplement insurance, or Medigap, is private insurance that covers expenses not paid for by Medicare (“gaps”).
You must have Medicare Part A and Part B to be eligible to purchase a Medigap plan.
For most, the best time to purchase a Medigap plan is during the Medicare open-enrollment period that occurs at age 65 or when employer-sponsored coverage ends.
Table of contents
When you’re signing up for Medicare Part A and Part B, it’s good to bear in mind that you’ll still be faced with some out-of-pocket expenses. Medicare pays most of the costs of covered healthcare services, but you're responsible for paying a portion. And those expenses can add up.
Roughly 1 in 5 Medicare enrollees choose to manage these costs by buying additional insurance coverage known as Medigap. Below, we review what Medigap, or Medicare supplement insurance, covers and how to choose a policy that fits you best.
What is Medigap?
Medigap is the nickname for Medicare supplement insurance. This is private insurance that people can use to help offset the costs that remain after Medicare Part A (hospital) and Part B (medical) have paid their shares. Having a Medigap plan can help keep your out-of-pocket costs down. However, people with Medicare Advantage plans (also known as Medicare Part C) cannot purchase Medigap insurance.
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Medigap premiums vary by:
State
Plan type
Enrollee age
Insurer
For a look at the range of premiums in your state, see the plan-by-plan breakdown below.
Types of Medigap policies
There are 10 Medigap plans, known as Plans A, B, C, D, F, G, K, L, M, and N. Their rules and benefits are the same in all but three states:
These states have their own standards for coverage and provide a narrower selection of plans.
Insurers don’t have to offer every Medigap plan, but they must offer Plans A, C, and F. (People who are newly eligible for Medicare are no longer able to buy Plans C and F, as of January 1, 2020.) Some companies also offer a type of Medigap policy called Medicare Select, which often has lower premiums than the standard plans but only provides coverage when you use in-network hospitals and providers.
What do Medigap plans cover?
Medigap policies typically help pay for costs such as:
Copayments: fixed amounts, like $20, that you pay out of pocket for a medical service after meeting your deductible
Coinsurance: the percentage, such as 25%, of a medical cost that you’re responsible for paying
Deductibles: the amount, like $200 or $1,000, that you must pay out of pocket for covered services before your health insurance plan will pay
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Some Medigap plans offer additional coverage, such as for emergency healthcare services received outside of the U.S. In general, Medigap covers your coinsurance once you’ve paid your Medicare deductible. Some plans (B, D, G, and N) will pay your Part A deductible, if you have one, as well. Plans C and F also pay Part A deductibles but, as mentioned, these plans aren’t available to new enrollees.
All Medigap plans cover 100% of Part A coinsurance and hospital costs after Medicare benefits are used, for as many as 365 days. Also, almost all Medigap plans cover 100% of the costs of:
Part B coinsurance and copayments
Blood (first 3 pints)
Part A hospice care coinsurance and copayments
The exceptions are Plans K and L, which cover these costs only partially.
How do I choose the best Medigap policy?
When picking a Medigap plan, think about both your current and future healthcare needs. It’s important to choose carefully, because there’s no guarantee you’ll be able to switch plans later.
The Center of Medicare & Medicaid Services (CMS) has a Medigap comparison table that can help you figure out which policy best fits your situation. The policies differ in their coverage for deductibles, skilled nursing care, excess charges, and healthcare received during foreign travel.
As mentioned above, all Medigap plans cover Medicare Part A hospital costs. But none of them — other than Plans C and F, which are no longer available to new enrollees — cover Medicare Part B deductibles.
If you want a lower monthly premium, feel comfortable with a high-deductible plan, and tend to use few healthcare services, consider Plans K and L. These plans are the only ones with out-of-pocket limits. For 2024, the Plan K out-of-pocket limit is $7,060. For Plan L, it’s $3,530 in 2024. After you’ve paid your Part B deductible and spent the maximum out-of-pocket amount, Plans K and L cover 100% of the costs of covered services for the rest of your policy year.
If you regularly travel outside of the U.S. and want to have access to emergency coverage, you may prefer Plans D, G, M, or N, which cover 80% of your costs. (Plans C and F also cover emergency healthcare during foreign travel, for those already enrolled in one of these plans.)
If you’re looking for 100% coverage for hospice and skilled nursing care, services that are often valuable at the end of life, Plans D, G, M, and N are solid choices.
If you want complete coverage of the Part A deductible, which is $1,632 per benefit period in 2024, you should avoid:
Plan A, which doesn't cover it
Plans K and M, which cover only 50% of it
Plan L, which covers only 75% of it
How do I enroll in a Medigap policy?
Many well-known insurance companies, including UnitedHealthcare, Mutual of Omaha, and CVS Health (the parent company of Aetna), sell Medigap plans. Coverage specifics are regulated by the CMS, and each insurance company chooses which plans to sell and what states to sell them in.
There are a few ways to find out what Medigap policies are available in your area:
Use the Medicare search tool: Enter your ZIP code in this Medicare search tool to see which Medigap plans are offered in your state.
Reach out to SHIP: Contact your State Health Insurance Assistance Program (SHIP) to find out which insurance companies sell Medigap policies in your state. Ask for a "Medigap rate comparison shopping guide” for free help choosing a policy.
Call your state insurance department: Ask your state’s insurance department if there are any records of complaints against the insurance companies you’re considering. With this information, you can steer clear of troublesome insurers.
Shop around at a few insurance companies, comparing their prices for your preferred plan. Once you’ve chosen a company, you’re ready to fill out an application for your Medigap policy.
Keep in mind that new Medigap policies don't cover prescription medications. For prescription medication coverage, you will probably need to enroll in Medicare Part D.
Can you buy a Medigap policy at any time?
If you haven’t turned 65 yet, you may not be able to purchase a Medigap policy. But if you are able to, it may cost more than the typical amount. This is the case even if you buy a Medigap policy within the first 6 months of having Medicare.
The best time to buy a policy is during your Medigap open-enrollment period, which is a one-time enrollment period, unlike the annual Medicare open-enrollment period. You have a 6-month window to purchase a policy after your Part B coverage starts. Within this period, you can buy any policy in your state, even if you have a preexisting health condition. If you want to buy a policy outside of your Medigap open-enrollment period, you’ll have to check with your state’s insurance department to determine the applicable laws.
During your Medigap open-enrollment period, you generally:
Get the best pricing
Receive more policy options
Won't need a health assessment (known as “medical underwriting”)
By contrast, if you wait to buy a plan, you might be denied, be subject to medical underwriting, or be charged a higher premium due to your health status. Though, there are certain situations in which an insurance company can't deny you a Medigap policy. These protections are called guaranteed issue rights.
Once you purchase a standardized Medigap plan, it automatically renews every year, as long as you pay the premiums. Couples will need two Medigap policies, as each policy covers only one person.
The bottom line
Medicare supplement insurance (Medigap) plans help cover healthcare costs that are left over after Medicare Part A and Part B have paid their portions. The best time to purchase a Medigap plan is during your Medigap open-enrollment period, which starts the first month you are 65 or older and have Medicare Part B coverage. As you select from the available plans, consider your financial status and health needs, such as if you would benefit from coverage for skilled nursing care or emergency healthcare during foreign travel.
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References
Clerveau, G., et al. (2023). A snapshot of sources of coverage among Medicare beneficiaries. Kaiser Family Foundation.
CMS.gov. (2023). K & L out-of-pocket limits announcements.
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Medicare.gov. (n.d.). Buying a Medigap policy.
Medicare.gov. (n.d.). Can I change my Medigap policy?
Medicare.gov. (n.d.). Compare Medigap plan benefits.
Medicare.gov. (n.d.). Costs.
Medicare.gov. (n.d.). Costs of Medigap policies.
Medicare.gov. (n.d.). Get ready to buy.
Medicare.gov. (n.d.). How do I buy a Medigap policy?
Medicare.gov. (n.d.). Learn how Medigap works.
Medicare.gov. (n.d.). Medigap in Massachusetts.
Medicare.gov. (n.d.). Medigap in Minnesota.
Medicare.gov. (n.d.). Medigap in Wisconsin.
Medicare.gov. (n.d.). What's Medicare supplement insurance (Medigap)?
National Association of Insurance Commissioners. (n.d.). Insurance departments.
New York State Department of Financial Services. (n.d.). What is Medicare Select?
U.S. Social Security Administration. (n.d.). Plan for Medicare.
