Medicare Supplement policies cover the costs that Original Medicare leaves you to pay

A Medicare Supplement policy (also called Medigap) pays toward the deductibles, copayments, and coinsurance that Medicare Part A and Part B require you to pay out of your own pocket. It does not add new benefits — it reduces what you owe on the benefits Medicare already covers. For example, if Medicare covers a hospital stay but charges you a $1,600 deductible, a Medigap policy can pay some or all of that $1,600.

The specific costs covered depend on which of the ten standardized Medigap plans you choose. Each plan is labeled A through N, and each covers a different combination of Medicare's cost-sharing. Plans are the same across all insurers — a Plan G from one company covers exactly what Plan G covers from another — so the main difference between insurers is price.

Key Takeaways

  • Medicare Supplement policies pay toward deductibles, copayments, and coinsurance for services that Original Medicare already covers.
  • Ten standardized plans (A through N) exist, and each covers a different set of out-of-pocket costs; Plan G and Plan N are the most common choices for new enrollees.
  • Medigap does not cover dental, vision, hearing aids, long-term care, or services Medicare itself does not cover.
  • You can only buy a Medigap policy if you have Original Medicare (Parts A and B), not if you are in a Medicare Advantage plan.
  • The best time to buy is during your initial enrollment period, when insurers cannot deny you or charge more based on health history.

What the ten Medigap plans cover

All ten plans cover Medicare Part A coinsurance (the daily cost-sharing for hospital stays beyond 60 days) and Medicare Part B coinsurance (typically 20 percent of the cost of doctor visits and outpatient services after you meet the deductible). Beyond that, coverage splits into categories.

Plans A, B, D, G, M, and N cover the Part B deductible, which is $240 in 2024 but changes yearly. Plans C and F covered the Part A deductible as well, but these plans are no longer sold to people new to Medicare as of 2020. Plans G, K, L, M, and N cover some or all of the Part A deductible ($1,600 in 2024). Plans D, G, K, L, M, and N cover some or all of skilled nursing facility coinsurance — the cost you owe after Medicare stops paying for a nursing home stay.

Plan G and Plan N are the two most commonly chosen by people newly turning 65, because they cover most of Medicare's standard cost-sharing. Plan G covers everything except the Part B deductible. Plan N covers everything except the Part B deductible and some copayments for doctor visits and emergency room use.

What Medicare Supplement does not cover

Medigap policies do not cover services that Original Medicare does not cover. That means no dental work, vision exams, hearing aids, or routine foot care. They do not cover long-term care (nursing home or in-home care for non-medical reasons), prescription drugs, or medical equipment like wheelchairs or oxygen unless Medicare itself covers it.

If you need dental or vision coverage, you would buy those separately — either as standalone plans or through a Medicare Advantage plan, which bundles medical, dental, and vision coverage together but works differently than Original Medicare plus Medigap.

How Medigap premiums work

You pay a monthly premium to the Medigap insurer, separate from your Medicare Part B premium. The amount varies by plan, by insurer, and by where you live. The same plan from different companies can cost $100 a month from one and $200 from another, so comparing quotes is worth the time.

Premiums also depend on your age and, in some states, your health history. Most states use community rating, meaning everyone in your area pays the same price regardless of age or health. A few states use age-rated pricing, where your premium rises as you age. Some use issue-age rating, where the price is locked to your age when you buy the policy and does not rise with age afterward.

Your premium may increase over time due to inflation and claims experience, but not because you turned a year older (unless you live in an age-rated state). Once you have a Medigap policy, you can switch to a different plan or insurer, but if you do so outside your initial enrollment period, the new insurer can deny you or charge more if you have health problems.

When you can buy Medigap without health questions

You have a Medigap open enrollment period of six months starting the first day of the month you turn 65 and are enrolled in Medicare Part B. During this window, any insurer must sell you any Medigap plan at the standard rate, regardless of your health history. This is the only time you have this protection.

If you miss this window, insurers can ask health questions, deny you coverage, or charge you more. Some states offer additional protections if you lose employer coverage or switch from a Medicare Advantage plan, but these vary. The safest approach is to buy during your initial six-month window.

Medigap versus Medicare Advantage

Medicare Supplement works only with Original Medicare. If you choose a Medicare Advantage plan instead, you cannot buy Medigap. Advantage plans bundle hospital, doctor, and prescription drug coverage into one plan, often with dental and vision included, and usually with a lower or zero monthly premium. But they use networks, require prior authorization for some services, and have different out-of-pocket limits.

Medigap gives you more flexibility — you can see any doctor who accepts Medicare — but costs more in monthly premiums. The choice depends on your health, your doctors, and what you value. You can switch between Original Medicare plus Medigap and Medicare Advantage during the annual open enrollment period (October 15 to December 7), but switching from Advantage back to Original Medicare plus Medigap outside that window can trigger health underwriting.

How to compare Medigap plans and insurers

Start by deciding which plan letter (A through N) makes sense for your situation. If you want the broadest coverage and can afford the premium, Plan G is often the choice. If you want lower premiums and do not mind some copayments, Plan N may suit you. Plans A, B, D, K, L, and M are less common but may fit specific needs.

Once you know your plan, get quotes from multiple insurers. Medicare.gov has a tool called the Medigap Plan Finder where you enter your zip code and see plans and prices from insurers in your area. You can also call insurers directly or work with a broker. Compare the monthly premium, any annual deductible (some plans have one), and the insurer's customer service ratings.

If you are within your six-month open enrollment period, you do not need to worry about health questions — any insurer must take you. If you are outside that window, you may want to call the insurer first to ask whether they will underwrite your process, or work with a broker who knows which insurers are more lenient in your state.

Frequently Asked Questions

Does Medicare Supplement cover prescription drugs?

No. Medigap covers cost-sharing for services Medicare covers, but not prescription drugs. You need a separate Part D prescription drug plan, which you can buy alongside Original Medicare and Medigap. You can enroll in Part D during your initial enrollment period or during the annual open enrollment period in the fall.

Can I switch Medigap plans or insurers after I buy one?

Yes, you can switch to a different plan or insurer at any time. However, if you switch outside your initial six-month open enrollment period, the new insurer can ask health questions and may deny you or charge more. Some states have limited switching rights, so check your state's rules. Switching plans within the same insurer is usually easier than switching insurers.

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

Your policy remains valid, but you may want to shop for a new one in your new state because prices and available plans vary by location. You can keep your current policy if you wish, but comparing local options might save you money. If you switch policies in your new state, the insurer can ask health questions unless you are still within your initial six-month enrollment period.

Is Medigap the same as Medicare Advantage?

No. Medigap works with Original Medicare and covers cost-sharing. Medicare Advantage replaces Original Medicare with a managed care plan that includes hospital, doctor, and drug coverage in one plan, often with dental and vision. You cannot have both at the same time. Medigap offers more doctor choice; Advantage plans typically cost less in premiums but use networks.

What if I buy Medigap and then decide I want Medicare Advantage instead?

You can switch during the annual open enrollment period (October 15 to December 7). If you switch back to Original Medicare plus Medigap later, you may face health underwriting and higher premiums unless you are still within your initial six-month enrollment period. Plan your choice carefully, because switching back can be costly.