Medicare Supplement and Medigap are the same insurance product

Medigap and Medicare Supplement are two names for the identical thing. Insurance companies and Medicare use both terms interchangeably. When you see one name, you are reading about the other.

Medigap policies are sold by private insurance companies, not by Medicare itself. They exist to cover the costs that Original Medicare (Part A and Part B) leaves you responsible for — copayments, coinsurance, and deductibles. Some Medigap plans also cover services Medicare does not pay for at all, like routine dental or vision care, depending on which plan letter you choose.

The confusion happens because "Medigap" is the older, more common name in everyday conversation, while "Medicare Supplement" is the formal term you will see on official Medicare documents and insurance company websites. Both refer to the same standardized plans, with the same coverage rules, sold by the same companies.

Key Takeaways

  • Medigap and Medicare Supplement are identical — they are two names for the same type of private insurance that works alongside Original Medicare.
  • These policies cover out-of-pocket costs that Original Medicare does not pay, such as copayments, coinsurance, and deductibles.
  • Plans are standardized by the federal government and labeled with letters (A, B, D, G, K, L, M, N), so the same plan letter offers the same coverage no matter which insurance company sells it.
  • You buy Medigap from a private insurance company during your enrollment window, which typically opens when you turn 65 or when you first become may be able to access for Medicare.

How Medigap works with Original Medicare

Medigap is designed to work only with Original Medicare (Part A and Part B). It does not work with Medicare Advantage plans, which are a different type of coverage altogether.

When you have Original Medicare plus a Medigap policy, here is how the payment flow works: you go to a doctor or hospital that accepts Medicare. Medicare pays its share of the bill first. Then your Medigap policy pays the portion that Medicare does not cover — the copay, coinsurance, or deductible. In many cases, you pay nothing out of pocket.

You pay two separate premiums each month: one to Medicare for Part B (and Part A if you did not pay it off during your working years), and one to the private insurance company for your Medigap plan. The Medigap premium varies by insurance company, by plan letter, and by your age and location.

The 10 standardized Medigap plan letters and what they cover

The federal government sets the rules for what each plan letter must cover. Plan A covers the same things whether you buy it from Aetna or from a regional carrier. This standardization means you can compare plans by letter alone — you do not need to read the fine print to know whether Plan G from one company covers the same ground as Plan G from another.

The 10 plans are labeled A, B, D, G, K, L, M, and N. (Plans C and F were discontinued for people who became may be able to access for Medicare after January 1, 2020, though some people who enrolled before that date can still hold them.) Each plan covers a different combination of Medicare's out-of-pocket costs.

Plan G is the most popular choice today for people newly turning 65, because it covers nearly all of Medicare's out-of-pocket costs except the Part B deductible. Plan N is less expensive but requires you to pay a copay at the doctor's office and a higher coinsurance amount for hospital stays. Plan A is the least expensive but covers fewer costs. The right plan depends on how much out-of-pocket spending you can afford and how often you expect to use medical care.

When you can buy a Medigap policy

Your best window to buy Medigap is your Medigap Open Enrollment Period, which lasts six months and starts the month you turn 65 and are enrolled in Medicare Part B. During this window, insurance companies must sell you any plan you want, and they cannot charge you more based on your health history or any medical conditions you have.

If you miss this window, you can still buy Medigap later, but insurance companies can deny you coverage or charge you a higher premium based on your health. Some states have additional protections that extend this window or allow you to switch plans under certain conditions, so the rules vary by location.

You buy Medigap directly from insurance companies — not from Medicare, not from a government office, and not from a broker (though brokers can help you compare). You can contact companies by phone or visit their websites to request quotes and enroll.

Medigap versus Medicare Advantage: which type of coverage is which

The confusion between Medigap and Medicare Advantage is common because both are private insurance options that work with Medicare. But they are fundamentally different products.

Medigap (Medicare Supplement) works alongside Original Medicare. You keep your Original Medicare coverage and add a Medigap policy on top. You can see any doctor or hospital that accepts Medicare, and Medicare and your Medigap policy split the bills.

Medicare Advantage is an alternative to Original Medicare. You give up Original Medicare and instead get all your coverage through a private insurance company's plan. Medicare Advantage plans often include prescription drug coverage (Part D) built in, and many include dental or vision benefits. But you are usually limited to doctors and hospitals in the plan's network, and you may need referrals to see specialists.

You cannot have both Medigap and Medicare Advantage at the same time. You choose one path or the other.

How Medigap premiums are set and what affects the cost

Medigap premiums vary widely depending on three main factors: the plan letter you choose, the insurance company you buy from, and your age and location. There is no single "correct" price — the same Plan G from Company A might cost $150 a month while the same plan from Company B costs $200 a month in your area.

Insurance companies use one of three pricing methods: community-rated (everyone in your area pays the same price regardless of age), issue-age-rated (your price is based on your age when you enroll and stays the same as you age), or attained-age-rated (your price increases as you get older). The pricing method affects how much your premium will rise over time.

You should get quotes from multiple companies before you enroll. Rates change year to year, and a company that is inexpensive today may not be inexpensive in five years. Some people switch plans or companies when their rates rise too much, though you may face medical underwriting if you switch outside your open enrollment window.

Frequently Asked Questions

Can I switch from a Medigap plan to Medicare Advantage later?

Yes, you can switch at any time during Medicare's Annual Enrollment Period (October 15 to December 7 each year). However, if you later want to switch back to Medigap, you may face medical underwriting and higher premiums, depending on your state and health history. Switching is possible but can be costly, so think carefully before you move.

Does Medigap cover prescription drugs?

No. Medigap covers only the out-of-pocket costs that Original Medicare leaves behind. Prescription drug coverage is Medicare Part D, which you buy separately from a pharmacy benefit manager. You can have both Medigap and Part D at the same time.

What happens to my Medigap if I move to a different state?

Your policy may not be valid in your new state, or the company may not sell that plan there. You will likely need to enroll in a new Medigap plan in your new state. Contact your current insurance company to find out what options are available where you are moving, and ask whether you have any protections during the transition.

Is Medigap the same as Medicaid?

No. Medicaid is a joint federal and state program for people with low income. Medigap is private insurance for people on Medicare. They are separate programs with different rules and different may be able to access requirements. Some people have both, but they serve different purposes.

Can I have more than one Medigap policy?

Technically yes, but it is not useful. Insurance companies will not pay duplicate claims, so a second policy would just be an extra premium with no benefit. Stick with one Medigap plan that meets your needs.