Medicare Supplement Plan K: Who’s It For?

December 12, 2019

Plan K is a type of Medicare Supplement plan. Medicare Supplement plans are additional insurance that people on Original Medicare (Part A and Part B) can purchase to give them more coverage for medical costs. (Some people are surprised to learn that Medicare does not pay 100% of seniors’ health care expenses.)

There are currently 10 Medicare Supplement plans. People also call them Medigap plans. The plans are named with letters ranging from Plan A to Plan N. For an overview of all the plans, see our Medicare Supplement Plans Guide.

Plan K works a little differently from most other Medicare Supplement plans. Its monthly premiums are some of the lowest, but people with Plan K pay a portion of their costs out of pocket when they need care (typically 50%).

Fortunately, there is a limit to how much you have to pay out of pocket on Plan K ($5,880 in 2020). Original Medicare has no limit on your annual spending, so having a Medigap plan that limits your yearly spending can give you some predictability and peace of mind.

Before we dive into Plan K specifics, here’s a question: are you a resident of Massachusetts, Minnesota, or Wisconsin? You can stop right here. Your states have their own Medicare Supplement plans and rules. Your local state insurance department can help you understand your options.

Plan K: Who is it for?

  • People on a tight budget: Plan K is a low-cost Medigap option that has affordable monthly premiums, but doesn’t cover as much as other plans.
  • People who don’t mind cost-sharing: Rather than covering extra costs completely, Plan K pays 50% toward your costs not covered by Medicare, and you pay the other 50%.
  • People who don’t travel much outside the US: Unlike many Medicare Supplement plans, Plan K doesn’t cover any emergency medical costs you incur abroad.

Elizabeth is 65, widowed, and recently retired because of health issues. Elizabeth applied for Medicare Part A and Part B and wants a Medicare Supplement plan as well. She has atrial fibrillation and has been in the hospital a handful of times. A low monthly premium and predictable costs are most important to her. After researching her options, Elizabeth decided to purchase Medigap Plan K, which will cover her Part A coinsurance and hospital costs, and limit the money she must pay out of pocket.

What Plan K covers

Is it covered?

Part A coinsurance and hospital costs (up to 365 days after Medicare coverage runs out)


Part B coinsurance or copayment


Blood (first 3 pints)


Part A hospice coinsurance or copayment


Skilled nursing facility coinsurance


Part A deductible


Part B deductible

Not covered

Part B excess charge

Not covered

Foreign travel exchange

Not covered

Out-of-pocket limit


Table created using information available at as of 12/12/19. 

What Plan K covers at 100%

Original Medicare covers hospital stays only up to a certain number of days, and you pay a greater portion (called your Part A coinsurance) the longer you stay. Plan K covers these hospital costs for 365 days after your Medicare benefits are exhausted. Every Medigap plan covers this expense.

If you have questions on how Part A works, see our Part A coverage explainer.

What Plan K covers at 50%

One unique element of Plan K is cost-sharing. That’s when you agree to chip in for a portion of your care costs in exchange for a lower premium.

As you can see in the chart above, Plan K covers many services at 50%. That means you pay half, and the insurance company pays half. For example, the Part A deductible is what you pay before Medicare begins paying for your hospital costs. In 2020, the Part A deductible is $1,408, so on Plan K, you would pay $704 (50% of $1,408).

Fortunately, there is a limit to how much you’re asked to pay each year, called your out-of-pocket limit. For Plan K, it’s $5,880. Once you shell out that much in a year, the insurance company pays any additional costs at 100%. Plan L works in a similar fashion, but with different coverage percentages and out-of-pocket costs.

What Plan K does not cover

Under Plan K, you are responsible for paying the Part B deductible ($198 in 2020), any Part B excess charges (upcharges from non-Medicare providers you see), and all bills for emergency care you receive abroad (also called “foreign travel exchange”).

If the above coverage is important to you, consider signing up for Plan F, if you are eligible. It is the only Medicare Supplement plan that covers all of them, but it will be discontinued for sale to those who become eligible for Medicare in 2020 and beyond.

Not eligible for Medicare until 2020 or after? Your next best option is Plan G, which covers Part B excess charges and 80% of foreign travel emergencies.

For more on how Part B works, consult our Part B guide.

Medicare Supplement Plan K: What you need to know before enrolling

If you are interested in Plan K, make sure to sign up for Original Medicare Part A and Part B first. Then, you’ll have six months to enroll in a Medicare Supplement plan, when you’re guaranteed to be accepted, no matter your health.

This six-month period is called your Medigap open enrollment period. You can enroll at other times, but it’s possible you’ll be denied or charged a higher rate because of your health.

Get Medigap Plan K

Pro Heading
Pro Bullet Low premiums
Pro Bullet Yearly out-of-pocket maximum limits
Con Heading
Con Bullet Covers many services at 50%, where other plans cover at 100%
Con Bullet Does not cover Part B excess charges or foreign travel emergencies

Medicare Supplement Plan K provides very basic coverage for a low premium, but you do have to pay some costs along the way. Plan K includes an annual out-of-pocket limit to keep your total costs predictable.


When was Medicare Plan K introduced?

Medicare Supplement Plan K has been around since 2003 when the Medicare Modernization Act established Medigap plans with cost-sharing. Cost-sharing is when you pay a portion of the medical costs, as you need care. It can be either a percentage or a flat fee.

Plan K and Plan L were the first such plans. Then, in 2008, two additional plans with cost-sharing features were added: Plan M and Plan N.

Content on this site has not been reviewed or endorsed by the Centers for Medicare & Medicaid Services, the United States Government, any state Medicare agency, or any private insurance agency (collectively "Medicare System Providers"). is a DBA of Clear Link Technologies, LLC and is not affiliated with any Medicare System Providers.

Kathryn Anne Stewart
Written by
Kathryn Anne Stewart
Kathryn Anne Stewart is a freelance writer who covers the intersection of health and money. She has written for Johns Hopkins Medicine, Weight Watchers, Newsmax Magazine, Franklin Prosperity Report, and the National Hemophilia Foundation, often crafting clear explanations of complex topics. When she's away from her desk, you can find her reading a library book, watching stand-up comedy, or cycling with her husband.
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