What Is Medigap?
Medicare Supplement Insurance Explained Simply
Medigap is another name for Medicare Supplement Insurance. It is extra insurance you can buy from a private insurance company to help pay some of your share of out-of-pocket costs in Original Medicare, such as copayments, coinsurance, and deductibles.
Medigap is called “supplement” insurance because it works alongside Original Medicare. It does not replace Medicare. Instead, it helps fill certain cost gaps that may remain after Medicare Part A and Part B pay their share.
This page explains what Medigap is, how it works, what it may help cover, what it does not cover, and why timing matters when buying a policy.
This page is educational only. We do not recommend any specific Medigap plan letter, insurance company, premium, or coverage choice.
What Does Medigap Mean?
The word Medigap comes from the idea that the policy helps fill some of the “gaps” in Original Medicare.
Original Medicare includes Part A and Part B. Part A is hospital insurance, and Part B is medical insurance. While Original Medicare helps cover many healthcare services, it does not pay for everything. You may still owe deductibles, copayments, coinsurance, or other costs.
That is where Medigap may help.
A simple way to remember it:
Medigap helps pay some of your share of costs under Original Medicare.
Medigap does not change what Original Medicare covers. It helps with certain costs after Original Medicare pays its share.
How Does Medigap Work?
Medigap works with Original Medicare.
When you receive Medicare-covered healthcare services, Original Medicare generally pays its share of the Medicare-approved amount first. Then your Medigap policy may pay part or all of the remaining amount you owe, depending on the policy you have. Medicare.gov explains that with most Medigap policies, the Medigap insurance company gets your Part B claim information directly from Medicare and then pays the amount owed under your policy.
A simple way to think about it:
Original Medicare pays first.
Medigap may help pay some remaining approved costs.
You pay anything left over.Medigap is designed to work with Original Medicare, not Medicare Advantage.
You Must Have Original Medicare to Buy Medigap
In most cases, you must have Original Medicare before you can buy a Medigap policy.
That generally means you must be enrolled in both:
Medicare Part A
Medicare Part B
Medicare.gov explains that you can only buy Medigap if you have Original Medicare, and that generally means you sign up for Medicare Part A and Part B before buying a Medigap policy.
This is one of the most important Medigap rules:
Medigap works with Original Medicare.
If you are trying to understand how Medigap fits into Medicare, start with that sentence.
What Does Medigap Help Cover?
Medigap policies help cover your share of costs for services covered by Original Medicare. These may include out-of-pocket costs such as copayments, coinsurance, and deductibles.
Depending on the policy, Medigap may help with costs related to:
Medicare Part A coinsurance
Medicare Part B coinsurance or copayments
Blood costs
Part A hospice care coinsurance or copayments
Skilled nursing facility care coinsurance
Part A deductible
Certain other Original Medicare cost-sharing amounts
Some Medigap policies may also cover certain services Original Medicare does not cover, such as emergency medical care when traveling outside the United States, depending on the policy.
This page is not comparing specific Medigap plan letters. The goal is to help you understand the basic purpose of Medigap.
What Medigap Does Not Cover
Medigap does not cover everything.
Medigap policies generally do not cover long-term care, routine vision or dental care, hearing aids, glasses, or private-duty nursing.
Medigap also does not usually include prescription drug coverage. Medigap policies sold after 2005 do not include prescription drug coverage. If you want prescription drug coverage, you can enroll in a separate Medicare Part D drug plan.
A simple way to remember it:
Medigap helps with some Original Medicare costs. It is not designed to cover every healthcare need.
That is why many people who choose Original Medicare also take time to understand Part D prescription drug coverage.
Medigap Is Not Medicare Advantage
Medigap and Medicare Advantage are often confused, but they are very different.
Medigap is supplemental insurance that works with Original Medicare.
Medicare Advantage, also called Part C, is another way to receive your Medicare coverage through a Medicare-approved private insurance company.
When you are getting started with Medicare, you can either buy Medigap or enroll in a Medicare Advantage plan, but you cannot have both. You also cannot use Medigap to pay Medicare Advantage copayments, deductibles, or premiums.
A simple way to compare them:
Original Medicare path:
Part A + Part B
Optional Medigap
Optional Part D
Medicare Advantage path:
Part C
Private Medicare-approved plan
Usually includes Part DThis is not a recommendation for one path over the other. It is simply the basic structure.
Can You Have Medigap and Medicare Advantage Together?
No.
Medigap and Medicare Advantage do not work together. If you have Medicare Advantage, you cannot use a Medigap policy to pay your Medicare Advantage out-of-pocket costs. You cannot buy Medigap while you are in a Medicare Advantage plan unless you are switching back to Original Medicare.
This is one of the biggest Medicare misunderstandings.
A simple rule:
Medigap works with Original Medicare, not Medicare Advantage.
If someone is comparing Medigap and Medicare Advantage, they are usually comparing two different ways to receive Medicare coverage.
Medigap and Part D Prescription Drug Coverage
Medigap and Medicare Part D are not the same.
Medigap helps with certain out-of-pocket costs in Original Medicare.
Part D helps cover prescription drugs.
Medigap policies sold after 2005 do not include prescription drug coverage. If you enroll in Medigap for the first time and want drug coverage, you can join a separate Medicare drug plan.
A simple way to think about it:
Original Medicare = Part A + Part B
Medigap = helps with some Original Medicare costs
Part D = helps with prescription drugsIf you choose Original Medicare, you may need to understand both Medigap and Part D.
Are Medigap Policies Standardized?
In most states, Medigap policies are standardized.
This means policies with the same letter offer the same basic benefits no matter where you live or which insurance company sells the policy. In most states there are 10 standardized Medigap plan types, named by letters: A through D, F, G, and K through N.
A simple way to remember it:
Same letter. Same basic benefits. Different company or price.
For example, a standardized Medigap Plan G from one insurance company has the same basic benefits as a standardized Medigap Plan G from another insurance company. The premium may differ, but the standardized basic benefits are the same.
Massachusetts, Minnesota, and Wisconsin standardize Medigap policies differently.
Why Do Medigap Prices Vary?
Even though Medigap policies are standardized in most states, premiums can vary widely.
Medigap premiums vary depending on the insurance company, the plan, and where you live. It also explains that benefits in each lettered plan are the same regardless of the insurance company, and the price is the only difference between policies with the same letter sold by different companies.
Medigap prices may vary based on factors such as:
The insurance company
The plan letter
Where you live
Available discounts
Whether medical underwriting applies
Whether you have a guaranteed issue right
Whether the policy is Medicare SELECT
Whether the policy has a high-deductible option
When you buy a Medigap policy, you pay a monthly premium to the private insurance company, and you also continue paying your Medicare Part B premium. Medicare does not pay your Medigap premium.
Medigap Covers One Person
A Medigap policy covers only one person.
If you and your spouse both want Medigap coverage, each of you would need to buy your own policy. Medicare.gov explains that a Medigap policy only covers one person, so spouses must each buy their own policy if both want coverage.
This is different from some employer or family insurance plans where more than one person may be covered under the same policy.
When Can You Buy Medigap?
The best time for many people to buy Medigap is during their Medigap Open Enrollment Period.
Under federal law, this is a six-month period that starts the first month you have Medicare Part B and are age 65 or older. During this time, you can enroll in any Medigap policy offered by an insurance company, and the insurance company cannot deny you coverage because of pre-existing health problems.
This is a one-time enrollment period. It does not repeat every year like the Medicare Open Enrollment Period.
A simple way to remember it:
Your Medigap Open Enrollment Period starts when you are 65 or older and enrolled in Part B. It lasts six months.
This timing matters because your rights may be different after this window ends.
What Happens If You Miss Your Medigap Open Enrollment Period?
If you miss your Medigap Open Enrollment Period, your options may be more limited.
Outside of your Medigap Open Enrollment Period, you may have to pay more, fewer policy options may be available, and an insurance company may be allowed to deny you a policy if you do not meet its medical underwriting requirements.
That is why timing matters.
Some people may still have special protections called guaranteed issue rights, but those depend on specific situations.
What Are Guaranteed Issue Rights?
Guaranteed issue rights are protections that may allow you to buy certain Medigap policies in certain situations.
These are situations where an insurance company cannot deny you a Medigap policy. These protections may apply outside your Medigap Open Enrollment Period in specific circumstances.
Examples may include certain situations where you lose other coverage or switch back to Original Medicare.
Because these rights can depend on your circumstances and state rules, it is important to keep letters, notices, emails, and other documents showing when coverage changed or ended.
What Is Medical Underwriting?
Medical underwriting is when an insurance company reviews your health history before deciding whether to sell you a policy, what options are available, or what premium you may pay.
During your Medigap Open Enrollment Period, companies cannot use medical underwriting to deny your application or charge you more because of pre-existing health problems.
Outside that window, medical underwriting may apply unless you have a guaranteed issue right or another protection under state law.
A simple takeaway:
Medigap timing can affect your choices.
This is one reason it is important to learn about Medigap before your enrollment window passes.
Can You Change Medigap Policies Later?
Sometimes, but it is not always simple.
In most cases, you do not have a federal right to switch Medigap policies unless you are within your six-month Medigap Open Enrollment Period or qualify under a specific situation or guaranteed issue right.
If you buy a new Medigap policy, you may have a 30-day “free look” period to decide whether to keep it. You should not cancel your first Medigap policy until you decide to keep the second one, and you may need to pay both premiums during that month.
The main takeaway:
Changing Medigap later may be possible, but it is not always guaranteed.
What If You Are Under 65?
If you have Medicare before age 65 because of disability or End-Stage Renal Disease, your Medigap options may depend on your state.
Federal law generally does not require insurance companies to sell Medigap policies to people under 65, although some states do offer Medigap rights to people under 65.
If you are under 65 and on Medicare, it is especially important to check your state’s rules.
What Is Medicare SELECT?
In some states, you may be able to buy a type of Medigap policy called Medicare SELECT.
Medicare SELECT policies may require you to use certain providers, and the premium may be lower. If you buy a Medicare SELECT policy, you may have the right to change your mind within 12 months and switch to a standard Medigap policy.
This is not available the same way everywhere, so it is another reason to compare options based on your location.
Why People Consider Medigap
People usually consider Medigap because Original Medicare can leave them responsible for certain out-of-pocket costs.
Medigap may help make those costs more predictable by covering some deductibles, copayments, and coinsurance. It can also appeal to people who want to use Original Medicare and have the flexibility to see providers that accept Medicare.
But Medigap is not the right fit for every person.
Some people may prefer Medicare Advantage. Others may have employer, retiree, union, Medicaid, or other coverage that changes the decision.
The goal is to understand how Medigap works so you can ask better questions.
Questions to Ask Before Buying Medigap
Before buying a Medigap policy, consider asking:
Do I have Original Medicare Part A and Part B?
Am I in my Medigap Open Enrollment Period?
Do I have a guaranteed issue right?
Which standardized Medigap policies are sold in my state?
What is the monthly premium?
How does the company set future premiums?
Does medical underwriting apply?
Are discounts available?
Is this a standard Medigap policy or Medicare SELECT?
Do I also need Part D prescription drug coverage?
How does this fit with my budget and healthcare needs?
The goal is not simply to choose a familiar company name. The goal is to understand how the policy works with your Medicare coverage.
Common Misunderstandings About Medigap
“Medigap is the same as Medicare Advantage.”
No. Medigap supplements Original Medicare. Medicare Advantage is another way to receive your Medicare coverage. You can either buy Medigap or enroll in Medicare Advantage, but you cannot have both.
“Medigap replaces Medicare.”
No. Medigap does not replace Medicare. It works with Original Medicare. Original Medicare pays first, and Medigap may help pay some remaining costs depending on your policy.
“Medigap includes prescription drug coverage.”
Generally, no. Medigap policies sold after 2005 do not include prescription drug coverage. If you want drug coverage, you can enroll in a separate Part D plan.
“I can buy Medigap anytime with no questions asked.”
Not always. Your Medigap Open Enrollment Period is usually the best time to buy. After that period, you may have fewer options, may pay more, or may be denied unless you have a guaranteed issue right or other protection.
“My spouse and I can share one Medigap policy.”
No. A Medigap policy covers only one person. If both spouses want Medigap coverage, each person needs a separate policy.
Common Questions About Medigap
What is Medigap?
Medigap is Medicare Supplement Insurance. It is extra insurance sold by private insurance companies to help pay some of your share of out-of-pocket costs in Original Medicare, such as copayments, coinsurance, and deductibles.
Is Medigap the same as Medicare Supplement Insurance?
Yes. Medigap and Medicare Supplement Insurance generally refer to the same type of coverage.
Do I need Original Medicare to buy Medigap?
Yes. You can only buy Medigap if you have Original Medicare. That generally means you have Medicare Part A and Part B.
Can I have Medigap with Medicare Advantage?
No. Medigap works with Original Medicare, not Medicare Advantage. You cannot use Medigap to pay Medicare Advantage copayments, deductibles, or premiums.
Does Medigap cover prescriptions?
Medigap policies sold after 2005 do not include prescription drug coverage. If you want prescription drug coverage, you can enroll in a separate Medicare Part D plan.
Are Medigap plans the same from every company?
In most states, Medigap policies are standardized by letter. Policies with the same letter have the same basic benefits no matter which insurance company sells them. However, premiums can vary by company and location.
When is the best time to buy Medigap?
For many people, the best time is during the six-month Medigap Open Enrollment Period, which starts the first month you have Medicare Part B and are age 65 or older. During this time, companies cannot deny you coverage because of pre-existing health problems.
The Simple Takeaway
Medigap is Medicare Supplement Insurance.
It works with Original Medicare to help pay some of your share of out-of-pocket costs, such as copayments, coinsurance, and deductibles. It does not replace Medicare, and it does not work with Medicare Advantage.
The most important things to remember are:
Medigap works with Original Medicare.
You generally need Part A and Part B to buy it.
Medigap helps with some Original Medicare out-of-pocket costs.
Medigap is different from Medicare Advantage.
Medigap usually does not include prescription drug coverage.
In most states, Medigap policies are standardized by letter.
Timing matters because your Medigap Open Enrollment Period does not repeat every year.
Understanding Medigap helps you better understand one of the main coverage paths available after you enroll in Medicare.
Need Help Understanding Medigap?
Medigap can be confusing because timing, premiums, underwriting, state rules, and prescription drug coverage all matter.
If you are trying to understand how Medigap works with Original Medicare, Part D, or Medicare Advantage, we can help connect you with a licensed Medicare professional who can answer questions based on your situation.