Medigap (Medicare Supplement Insurance) is extra insurance you can buy from a private health insurance company to help pay your share of out-of-pocket costs in Original Medicare, like copayments, coinsurance, and deductibles. You can only buy Medigap if you have Original Medicare. The best time to buy a Medigap policy is during your 6-month Medigap Open Enrollment Period.
What matters most
What Medigap does
Medigap helps pay your share of out-of-pocket costs in Original Medicare, like copayments, coinsurance, and deductibles. If you have a Medigap policy and get care, Medicare will pay its share of the Medicare-approved amount. In most Medigap policies, your policy will then pay your doctor whatever amount you owe under your policy, and you're responsible for any costs that are left.
It works only with Original Medicare
You can only buy Medigap if you have Original Medicare. Generally, that means you have to sign up for Part A and Part B before you can buy a Medigap policy. When you're getting started with Medicare, you can either buy Medigap or enroll in a Medicare Advantage Plan, but you can't have both.
The best time to buy
The best time to buy a Medigap policy is during your 6-month Medigap Open Enrollment Period. During this time, you can enroll in any Medigap policy and the insurance company can't deny you coverage due to pre-existing health problems. After this period, you may not be able to buy a Medigap policy, or it may cost more.
Want the detail? How it works, a worked example and common mix-ups are in .
Words on this page
Medigap Open Enrollment Period
the one-time, 6-month period that starts when you're 65 or older and signed up for Part B, when you can enroll in any Medigap policy
Guaranteed issue rights
limited situations when insurance companies must sell you certain Medigap policies and can't charge you more because of health problems
Premium
the monthly amount you pay to keep a policy
Who can answer for your situation
Your State Health Insurance Assistance Program (SHIP) gives free help choosing a Medigap insurance company in your area. Your State Insurance Department has a list of companies selling policies in your state. You can also call 1-800-MEDICARE (1-800-633-4227).
Medigap doesn't cover drugs, so you would add a separate Part D plan.
How it helps pay your costs
Medigap (Medicare Supplement Insurance) is extra insurance you can buy from a private health insurance company to help pay your share of out-of-pocket costs in Original Medicare, like copayments, coinsurance, and deductibles. If you have a Medigap policy and get care, Medicare will pay its share of the Medicare-approved amount for covered health care costs. In most Medigap policies, your policy will then pay your doctor whatever amount you owe under your policy, and you're responsible for any costs that are left.
You pay the private insurance company a separate monthly premium for your Medigap policy, in addition to the monthly Part B premium you pay to Medicare. A Medigap policy only covers one person, so if you and your spouse both want Medigap coverage, you each have to buy your own policy. Once you buy a policy, you'll keep it as long as you pay your Medigap premiums. All standardized Medigap policies are automatically renewed every year, even if you have health problems.
Plans with the same letter
All plans with the same letter offer the same basic benefits, no matter where you live or which insurance company you buy the policy from. Price is the only difference between policies with the same letter sold by different companies. Costs can vary widely between companies, so contact more than one company to get an estimate. In Massachusetts, Minnesota, and Wisconsin, Medigap policies are standardized in a different way.
When to buy
The best time to buy a Medigap policy is during your Medigap Open Enrollment Period. This is the 6-month period that starts the first day of the month you're 65 or older and signed up for Part B. During this time, you can enroll in any Medigap policy and the insurance company can't deny you coverage due to pre-existing health problems. After this period, you may not be able to buy a Medigap policy, or it may cost more.
Your Medigap Open Enrollment Period is a one-time enrollment. It doesn't repeat every year, like the Medicare Open Enrollment Period. After it ends, insurance companies don't have to sell you a Medigap policy, unless you have Medigap protections, called guaranteed issue rights. These are limited situations when insurance companies must sell you certain Medigap policies, cover your pre-existing health conditions, and can't charge you more because of health problems.
An example
Say you turn 65 in June and sign up for Part B then. Your 6-month Medigap Open Enrollment Period starts the first day of that month, so it runs June through November. During this time, you can enroll in any Medigap policy and the insurance company can't deny you coverage due to pre-existing health problems. After this period, you may not be able to buy a Medigap policy, or it may cost more.
Common mix-ups
These are the pairs people most often mix up.
Medigap vs. Medicare Advantage
A Medigap policy is different from a Medicare Advantage Plan. A Medicare Advantage Plan is another way to get your Medicare coverage besides Original Medicare. A Medigap policy is a supplement to Original Medicare coverage. You can't have both, and you can't use Medigap to pay your Medicare Advantage Plan copayments, deductibles, and premiums.
Medigap and drug coverage
Medigap plans sold after 2005 don't include prescription drug coverage. So if you enroll in Medigap for the first time, it won't include drug coverage. If you want prescription drug coverage, you can join a separate Medicare drug plan (Part D).
If you're still working
Your one-time Medigap Open Enrollment Period starts once you sign up for Part B and lasts for 6 months, even if you sign up for Part B while you still have employer coverage. Employer coverage often gives coverage similar to Medigap, so you probably don't need to get a Medigap policy while you have it.
Original Medicare (Part A and Part B) on its own has no yearly limit on what you pay out of pocket. Medicare Advantage plans have a yearly limit; once you reach it, you pay nothing for covered services for the rest of the year. And in 2027, your out-of-pocket spending on covered Part D drugs is capped at $2,400.
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Can I trust this?
Checked by TapTap. Every fact on this page was checked against the official sources it quotes, on October 1, 2026.
Checking compares each fact with the official source it quotes. It isn’t medical or legal advice.
Dates
Takes effect
January 1, 2027
Next check due
September 30, 2027
Plan year
2027
Sources
Centers for Medicare & Medicaid Services
Choosing a Medigap Policy: A Guide to Health Insurance for People with Medicare (CMS Product No. 02110)
1 What the source says · Section 2: Medigap basics, How does Medigap work? (p. 5)
Medicare Supplement Insurance (Medigap) is extra insurance you can buy from a private health insurance company to help pay your share of out-of-pocket costs in Original Medicare, like copayments, coinsurance, and deductibles.
Checked October 1, 2026
5 What the source says · Section 2: Medigap basics, What else do I need to know if I want to buy a Medigap policy? (p. 9)
You pay the private insurance company a separate monthly premium for your Medigap policy in addition to the monthly Part B premium you pay to Medicare.
Checked October 1, 2026
7 What the source says · Section 2: Medigap basics, Medigap policies are standardized (p. 6)
All plans with the same letter offer the same basic benefits, no matter where you live or which insurance company you buy the policy from. Price is the only difference between policies with the same letter sold by different companies. In Massachusetts, Minnesota, and Wisconsin, Medigap policies are standardized in a different way.
You can only buy Medigap if you have Original Medicare. Generally, that means you have to sign up for Medicare Part A (Hospital Insurance) and Part B (Medical Insurance) before you can buy a Medigap policy.
Checked October 1, 2026
10 What the source says · Get Medigap Basics
During this time, you can enroll in any Medigap policy and the insurance company can't deny you coverage due to pre-existing health problems. After this period, you may not be able to buy a Medigap policy, or it may cost more.
Checked October 1, 2026
11 What the source says · Get Medigap Basics
Your Medigap Open Enrollment Period is a one-time enrollment. It doesn't repeat every year, like the Medicare Open Enrollment Period.
If you have a Medigap policy and get care, Medicare will pay its share of the Medicare-approved amount for covered health care costs. In most Medigap policies, you agree to have the Medigap insurance company get your Part B claim information directly from Medicare. Then, your Medigap policy will pay your doctor whatever amount you owe under your policy and you're responsible for any costs that are left.
Checked October 1, 2026
4 What the source says · Learn How Medigap Works
A Medigap policy only covers one person, so if you and your spouse both want Medigap coverage, you each have to buy your own policy.
Checked October 1, 2026
6 What the source says · Learn How Medigap Works
Once you buy a policy, you'll keep it as long as you pay your Medigap premiums. All standardized Medigap policies are automatically renewed every year, even if you have health problems.
Checked October 1, 2026
14 What the source says · Medigap & other Medicare coverage, Medigap & Medicare Advantage Plans
A Medigap policy is different from a Medicare Advantage Plan (Part C). A Medicare Advantage Plan is another way to get your Medicare coverage besides Original Medicare. A Medigap policy is a supplement to Original Medicare coverage. When you're getting started with Medicare, you can either buy Medigap or enroll in a Medicare Advantage Plan, but you can't have both.
Checked October 1, 2026
15 What the source says · Medigap & other Medicare coverage, Medigap & Medicare Advantage Plans
You can't use Medigap to pay your Medicare Advantage Plan copayments, deductibles, and premiums.
Checked October 1, 2026
16 What the source says · Medigap & other Medicare coverage, Medigap & prescription drug coverage
Medigap plans sold after 2005 don't include prescription drug coverage. So, if you enroll in Medigap for the first time, it won't include drug coverage. If you want prescription drug coverage, you can join a separate Medicare drug plan (Part D).
8 What the source says · How to buy a Medigap policy, Shop by price
Costs can vary widely between companies, so contact more than one company to get an estimate.
Checked October 1, 2026
12 What the source says · How to buy a Medigap policy
After your Medigap Open Enrollment Period ends, insurance companies don't have to sell you a Medigap policy, unless you have Medigap protections, called "guaranteed issue rights."
Checked October 1, 2026
13 What the source says · Definition: Guaranteed issue rights
Limited situations when insurance companies must sell you certain Medigap policies, cover your pre-existing health conditions, and can't charge you more because of health problems.
9 What the source says · Your answer: You can buy a Medigap policy once you sign up for Medicare.
The best time to buy a Medigap policy is during your Medigap Open Enrollment Period. This is the 6-month period that starts the first day of the month you're 65 or older and signed up for Part B. After this period, your options to buy a Medigap policy may be limited and the policy may cost more.
Checked October 1, 2026
17 What the source says · Your answer (still working, with employer or union coverage): You can buy Medigap when you sign up for Medicare Part B.
Your one-time Medigap Open Enrollment Period starts once you sign up for Part B and lasts for 6 months, even if you sign up for Part B while you still have employer coverage. Employer coverage often gives coverage similar to Medigap, so you probably don't need to get a Medigap policy now.
Checked October 1, 2026
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General education, not individualized advice. For your own situation, you can call 1-800-MEDICARE or your State Health Insurance Assistance Program (SHIP).
