Medigap is private insurance that pays for costs Medicare leaves behind

Medigap (also called Supplemental Insurance) is a policy you buy from a private insurance company to cover the bills Medicare does not pay. Medicare covers a lot, but it leaves gaps: you still owe deductibles, copayments, and coinsurance. Medigap steps in and pays those out-of-pocket costs so you do not have to.

You buy Medigap on your own — it is not run by Medicare or the government. The insurance company you choose collects the monthly premium directly from you. Medigap only works alongside Original Medicare (the government plan with Part A hospital coverage and Part B doctor visits). If you have a Medicare Advantage plan instead, you cannot use Medigap.

Key Takeaways

  • Medigap covers deductibles, copayments, and coinsurance that Medicare does not pay, but it does not cover dental, vision, or hearing aids.
  • You buy Medigap from a private insurance company and pay a monthly premium in addition to your Medicare Part B premium.
  • Medigap plans are standardized by the federal government, so Plan G from one company covers the same things as Plan G from another company — only the price differs.
  • You can enroll in Medigap during your initial enrollment period when you turn 65, or during the open enrollment period each year, though waiting may cost you more.
  • Medigap does not cover long-term care, dental work, vision care, hearing aids, or prescription drugs — those need separate coverage.

What Medigap covers and what it does not

Medigap pays the bills that come after Medicare pays its share. If Medicare covers 80 percent of a doctor visit and you owe the remaining 20 percent, Medigap can cover that 20 percent. It also pays the annual deductible you owe before Medicare starts paying at all. Some Medigap plans cover emergency care when you travel outside the United States.

Medigap does not cover prescription drugs — you need Part D for that. It does not cover dental work, vision care, hearing aids, or long-term nursing home care. It does not cover routine physical exams or preventive care that Medicare already covers at no cost to you. If you need any of those services, you will need to pay out of pocket or buy separate coverage.

The ten standardized Medigap plans and what they cost

The federal government has set up ten standard Medigap plans, labeled A through N. Each plan covers a fixed set of costs. Plan A is the most basic and cheapest. Plan G covers more than Plan A and costs more. Plan N covers even more. The exact benefits of each plan are the same no matter which insurance company sells it to you — so Plan G from Company X covers identical services as Plan G from Company Y.

What does change between companies is the monthly premium you pay. Two insurance companies selling Plan G may charge you $120 per month and $150 per month for the identical coverage. Shopping around for price is how you save money on Medigap. Premiums also vary by age, location, and whether you are male or female — each state sets its own rules about how much variation is allowed.

Most people choose Plan G or Plan N because they cover the most common out-of-pocket costs. Plan A is cheaper but leaves you responsible for more bills. Your doctor or local senior center can help you compare which plan makes sense for your health situation and budget.

When you can enroll in Medigap and what happens if you wait

The best time to enroll in Medigap is during your Initial Enrollment Period, which starts the month you turn 65 and enroll in Medicare Part B. During this window — usually six months long — insurance companies must sell you a Medigap plan at the standard rate, and they cannot refuse you or charge you more because of health problems you already have.

If you miss that window, you can still buy Medigap during the yearly Open Enrollment Period (October 15 to December 7 each year). However, after your Initial Enrollment Period ends, insurance companies can charge you more if you have a pre-existing condition, or they can refuse to sell you a plan altogether. Some states have additional protections, but not all. The longer you wait, the more expensive Medigap becomes.

If you are still working and covered by your employer's health plan at 65, you may have a special enrollment period that extends your Initial Enrollment Period. Ask your employer's benefits office or call Medicare at 1-800-MEDICARE to find out whether you may have access to.

How Medigap works with your Medicare bills

When you see a doctor, Medicare processes the claim first. Medicare pays its share, and you receive a notice showing what you owe. You then send that notice to your Medigap insurance company, which pays the amount your Medigap plan covers. In most cases, the doctor's office and your Medigap company coordinate this automatically, so you do not have to file anything yourself.

You will still receive a bill from your doctor's office or hospital, but it will show only the amount Medigap does not cover — usually zero if your plan covers that type of service. If your Medigap plan does not cover a particular cost (for example, Plan A does not cover the Part B deductible), you owe that bill yourself.

Medigap versus Medicare Advantage: which path to choose

If you have Original Medicare and want to add coverage for out-of-pocket costs, Medigap is one option. The other is to switch to a Medicare Advantage plan (Part C), which is an all-in-one alternative to Original Medicare run by private insurance companies. You cannot have both Medigap and Medicare Advantage at the same time.

Medigap works best if you want to see any doctor who accepts Medicare, because Original Medicare has no network restrictions. Medicare Advantage plans usually have networks, meaning you pay more if you see an out-of-network doctor. Medigap premiums are usually higher than Medicare Advantage premiums, but you have more freedom in choosing providers. Medicare Advantage often includes dental and vision coverage that Medigap does not. The choice depends on your health needs, which doctors you want to see, and your budget.

How to find and compare Medigap plans in your area

Start by visiting Medicare.gov and using their Medigap plan finder tool. Enter your state and zip code, and the tool will show you which insurance companies sell Medigap plans in your area and what they charge for each plan type. You can compare prices side by side.

You can also call 1-800-MEDICARE and ask for a list of Medigap insurers in your state. Your State Health Insurance information Program (SHIP) — a free counseling service — can walk you through the plans and help you understand which one fits your situation. To find your local SHIP, search "[your state] SHIP" online or call 1-800-MEDICARE and ask for the number.

Before you enroll, confirm that the insurance company is licensed to sell Medigap in your state. Your state insurance commissioner's office maintains a list of approved insurers. Never buy Medigap from someone who contacts you unsolicited by phone or email.

Frequently Asked Questions

Can I switch from one Medigap plan to another?

Yes, you can switch Medigap plans at any time, though insurance companies can charge you more or deny coverage if you have developed a health condition since you first enrolled. Your best opportunity to switch without penalty is during the yearly Open Enrollment Period (October 15 to December 7). Some states offer additional switching windows. Contact your current Medigap company or your state insurance commissioner's office to learn what applies where you live.

Do I still pay Medicare premiums if I have Medigap?

Yes. You pay your Medicare Part B premium to Medicare, and you pay your Medigap premium to the private insurance company. Medigap does not replace Medicare — it works alongside it. If you have Part D prescription drug coverage, you pay that premium separately too.

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

Your Medigap policy may not be valid in your new state, because each state regulates which plans can be sold and at what price. Contact your insurance company before you move to find out whether they sell Medigap in your new state. If they do not, you will need to enroll in a new plan. Your new state may have a special enrollment period for people who move, so ask your state insurance commissioner's office.

Does Medigap cover care outside the United States?

Most Medigap plans do not cover care outside the U.S., but some plans (usually Plan C, D, F, G, M, and N) cover emergency care during the first 60 days of travel outside the country. Check your plan documents or call your insurance company to confirm what your specific plan covers before you travel.

Can an insurance company drop me from my Medigap plan?

Insurance companies can drop you only in rare circumstances, such as if you do not pay your premium or if you move out of the state where the company is licensed to sell Medigap. They cannot drop you because you get sick or file too many claims. If your company stops selling Medigap in your state, they must give you at least 30 days' notice and help you move to another plan.