Medicare Supplement and Medigap are the same insurance product

Medicare Supplement and Medigap are two names for the exact same type of insurance. There is no difference between them. Insurance companies sell these policies under both names, and you will see them used interchangeably on websites, in documents, and when you talk to agents. The term "Medigap" comes from the idea that these policies fill the gaps in Original Medicare coverage — the costs Medicare Part A and Part B do not pay.

If you have Original Medicare (Part A and Part B), a Medigap policy helps pay some or all of the costs you would otherwise owe out of your own pocket: deductibles, copayments, and coinsurance. The policy does not replace Original Medicare; it works alongside it. When you go to the doctor or hospital, you still use your Medicare card, and both Medicare and your Medigap policy pay their share of the bill.

Key Takeaways

  • Medicare Supplement and Medigap are identical products sold by private insurance companies under two different names.
  • These policies work only with Original Medicare (Part A and Part B), not with Medicare Advantage plans.
  • Medigap policies are standardized by the federal government, so Plan G from one company covers the same things as Plan G from another company.
  • You can change Medigap policies or switch companies, but timing matters — your best rates and easiest entry are within six months of turning 65 or enrolling in Medicare Part B.

Why the two names exist

"Medigap" is the older, more common name and comes directly from what the policy does: it fills gaps in Medicare coverage. The term "Medicare Supplement" is more formal and is used by the government, insurance regulators, and some insurance companies when they want to be precise about what the product is.

Both names appear in official documents. When you look at the Medicare website or your state insurance department's materials, you will see "Medicare Supplement." When you call an insurance agent or read a company's marketing materials, you are more likely to hear "Medigap." Neither name is wrong, and neither one means something different from the other.

How Medigap differs from Medicare Advantage

The confusion between Medigap and Medicare Advantage is much more important than the difference between the two names. These are two completely different ways to get Medicare coverage, and you cannot have both at the same time.

Original Medicare with Medigap means you keep your Medicare Part A and Part B coverage and buy a separate Medigap policy from a private company to cover some of your out-of-pocket costs. You can see any doctor or hospital that accepts Medicare, and there are no networks or referrals required.

Medicare Advantage is a different type of plan sold by private insurance companies. It replaces your Original Medicare coverage entirely. Medicare Advantage plans usually have lower premiums than Medigap, but they come with networks, copayments, and often require referrals to see specialists. You cannot use a Medigap policy if you are enrolled in Medicare Advantage.

The standardized plans: what you are actually buying

The federal government sets the rules for what each Medigap plan must cover. There are ten standardized plans, labeled A, B, D, G, K, L, M, N, and two high-deductible versions of G and F. Plan G from Blue Cross covers exactly the same things as Plan G from Aetna or any other company — the only differences are the premium you pay and the customer service you get.

This standardization means you can compare prices across companies without worrying that a cheaper plan covers less. It also means that if you switch from one insurance company to another, you can keep the same plan letter and know you are getting the same coverage.

Plan G is currently the most popular choice for people new to Medicare, because it covers most of the costs that Original Medicare does not. Plan N is also common and costs less than Plan G, but it leaves you responsible for some copayments. Your choice depends on how much you want to pay in premiums versus how much you want to pay out of your pocket when you use care.

When you can buy Medigap at the best rates

Your age and the timing of your Medicare enrollment determine whether insurance companies must sell you a Medigap policy and at what price. The best time to buy is within six months of turning 65 or within six months of enrolling in Medicare Part B, whichever is later. During this window, called the Medigap Open Enrollment Period, insurance companies must sell you any plan they offer, and they cannot charge you more based on your health history.

If you miss this window, you can still buy Medigap, but the rules change. Some states have protections that let you buy a policy without health questions, but other states do not. In states without protections, insurance companies can deny you coverage or charge you more if you have a pre-existing condition. This is why timing matters — waiting costs money or access.

Switching Medigap policies or companies

You can change your Medigap policy or move to a different insurance company, but the rules depend on whether you are still in your Open Enrollment Period. If you are within six months of first enrolling in Medicare Part B, you have the strongest protections: companies must sell you any plan, and they cannot use your health history against you.

After that window closes, switching becomes harder in some states and easier in others. Some states require insurance companies to let you switch to a less expensive plan without health questions. Other states have no such rule. Before you switch, contact your state insurance department or a State Health Insurance information Program (SHIP) counselor to learn what your state allows. SHIP counselors are free and can walk you through your options.

What Medigap does not cover

Medigap covers the gaps in Original Medicare, but it does not cover everything. It does not pay for dental, vision, hearing aids, or long-term care. It does not cover prescription drugs — for that, you need a separate Medicare Part D plan. It also does not cover care outside the United States, though some plans offer limited coverage for emergencies abroad.

If you need dental or vision coverage, you will have to buy those separately or go without. Some people buy standalone dental and vision plans; others pay out of pocket. This is a real cost to factor in when you decide whether Medigap is right for you.

Frequently Asked Questions

Can I have both Medigap and Medicare Advantage at the same time?

No. You must choose one or the other. If you have Medicare Advantage and buy a Medigap policy, the Medigap policy will not pay anything because Medicare Advantage is not Original Medicare. If you want to switch from Medicare Advantage to Original Medicare with Medigap, you can do so during the annual Medicare Open Enrollment Period (October 15 to December 7), and you will enter a new Medigap Open Enrollment Period.

Do I need Medigap if I have Original Medicare?

No, it is optional. You can stay on Original Medicare alone and pay the costs yourself. Many people do this, especially if they are healthy and do not go to the doctor often. But if you use care regularly, Medigap can save you money by capping your out-of-pocket costs. The decision depends on your health, your budget, and how much financial risk you are comfortable taking.

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

Your policy stays in effect, but you may want to shop for a new one in your new state. Rates vary by state, and your current company may not offer the same plans in your new home. You have the right to switch to a different plan or company when you move, and some states protect you from health questions during this transition. Contact your new state's insurance department to learn the rules.

Is Medigap more expensive than Medicare Advantage?

Usually, yes. Medigap premiums are typically higher than Medicare Advantage premiums, sometimes significantly. But Medigap has no networks and no referrals, so you may spend less on copayments and coinsurance when you use care. The total cost depends on how much medical care you actually use. If you see many doctors or take many medications, Medigap may cost less overall. If you rarely use care, Medicare Advantage may be cheaper.

Can I change my Medigap plan if my health gets worse?

It depends on your state and how long you have had Medicare. If you are still in your Medigap Open Enrollment Period (within six months of enrolling in Part B), you can switch to any plan without health questions. After that, some states let you switch to a less expensive plan without health questions, but you cannot switch to a more expensive plan without undergoing health review. Ask your state insurance department or SHIP what your state allows.