Medigap Coverage Explained: What These Plans Actually Pay For

If you have Original Medicare (Parts A and B), you’ve probably noticed it doesn’t cover everything. That’s where Medigap (also called Medicare Supplement Insurance) comes in.

This guide walks you through what is covered in Medigap, what isn’t, and how the different benefits fit together so you can better understand your potential out‑of‑pocket costs.

What Is Medigap, in Plain Language?

Medigap is optional insurance you can buy from private companies to help pay for some of the “gaps” in Original Medicare, such as:

• Deductibles
• Copayments
• Coinsurance

You must:

• Be enrolled in Medicare Part A and Part B, and
• Pay a monthly premium for your Medigap policy (in addition to your Part B premium).

Medigap does not replace Medicare. Instead, Medicare pays its share of covered services first, and then your Medigap plan may help pay some or all of the remaining amount, depending on the plan.

The Core Benefits Most Medigap Plans Cover

While each standardized Medigap plan is a bit different, many of them share a set of core benefits. Below is an overview of some of the most important areas where Medigap commonly helps.

1. Medicare Part A Coinsurance and Hospital Costs

Original Medicare Part A covers inpatient hospital care, but you can still owe coinsurance after a certain number of days.

Most Medigap plans cover:

• Part A coinsurance and hospital costs for up to an additional 365 days after Medicare benefits are used up.

This means if you have a long hospital stay, your Medigap plan can help prevent very large out‑of‑pocket bills.

2. Medicare Part B Coinsurance or Copayments

With Part B (outpatient care, doctor visits, some preventive services), you usually pay 20% coinsurance after meeting the Part B deductible.

Most Medigap plans cover some or all of that 20% Part B coinsurance for:

• Doctor visits
• Outpatient services
• Durable medical equipment (subject to Medicare rules)
• Many preventive services once the Part B deductible is met

Some specific Medigap plans pay this coinsurance in full, while others cover a percentage (like 50% or 75%), so your exact coverage depends on the plan letter (A, B, G, N, etc.).

3. Blood (First 3 Pints)

Original Medicare typically does not cover the first 3 pints of blood you may need in a year.

Most Medigap plans cover:

• All or part of the cost of the first 3 pints of blood each year.

This can be important if you ever need a transfusion or surgery that involves blood.

4. Part A Hospice Care Coinsurance or Copayments

Medicare Part A covers hospice, but there may be small copayments or coinsurance for certain medications or respite care.

Many Medigap plans help pay:

• Part A hospice coinsurance or copayments, reducing your share of those costs.

5. Skilled Nursing Facility (SNF) Care Coinsurance

If you need skilled nursing facility care (for example, after a hospital stay), Medicare Part A may cover it, but after a certain number of days, daily coinsurance applies.

Some Medigap plans cover:

• Part A skilled nursing facility coinsurance for eligible stays.

This can help significantly with post‑hospital recovery costs.

6. Medicare Part A Deductible

The Part A deductible is the amount you pay when you’re admitted as an inpatient before Medicare starts paying for your hospital stay.

Many Medigap plans:

• Cover all or part of the Part A deductible.

Plans differ: some cover it fully, some partially, and a few do not cover it at all.

7. Medicare Part B Deductible

(Only in certain older plans)

There used to be Medigap plans that covered the Part B deductible.

• Some people who have older Medigap Plans C or F may have coverage for the Part B deductible.
• These plans are not available to people who became newly eligible for Medicare on or after January 1, 2020, but those who already have them may keep them.

If you have a newer Medigap plan, it generally will not cover the Part B deductible.

8. Part B “Excess Charges”

Some doctors who accept Medicare can charge up to a certain amount above the Medicare‑approved amount (these are called “excess charges” in some states).

Certain Medigap plans cover:

• Part B excess charges, so you may not have to pay those extra amounts out of pocket, as long as the service is Medicare‑covered.

Not all Medigap plans include this benefit, so it’s something to look for if you are concerned about seeing providers who might bill above the Medicare‑approved rate.

9. Foreign Travel Emergency Care

Original Medicare generally provides very limited coverage outside the U.S.

Some Medigap plans include coverage for:

• Emergency medical care in foreign countries, up to plan limits and under specific conditions.

Typically, this is:

• Only for emergency care,
• Subject to deductibles, and
• Capped at a lifetime maximum benefit amount.

If you travel internationally, this benefit can be an important consideration.

Quick Medigap Coverage Snapshot

While there are multiple standardized Medigap plans (A, B, C, D, F, G, K, L, M, N), not all plans cover everything below. This table gives a simplified overview of common Medigap benefits. It’s not a replacement for an actual plan’s outline of coverage, but it can help you see the big picture.

*Exact coverage depends on the plan letter and policy details in your state.

What Medigap Does Not Cover

It’s just as important to know what Medigap does not cover.

In general, Medigap does not cover:

• Prescription drugs (outpatient medications you fill at a pharmacy)
  • For that, people typically consider a separate Medicare Part D plan.
• Routine vision care (eyeglasses, standard eye exams)
• Routine dental care (cleanings, fillings, dentures)
• Hearing aids and routine hearing exams
• Long‑term custodial care (help with bathing, dressing, eating, if it’s the only care you need)
• Private‑duty nursing
• Most non‑Medicare‑covered services (alternative therapies, cosmetic surgery, etc.)

Medigap is designed to supplement Medicare‑covered services, not to expand what Original Medicare covers. If Medicare doesn’t cover a service at all, Medigap generally will not cover it either.

How Medigap Works with Original Medicare

To understand Medigap coverage, it helps to see the flow of payment for a typical covered service:

1. You visit a doctor or have a procedure that is covered by Medicare.
2. Medicare approves the service and pays its share (for example, 80% under Part B after deductibles).
3. Your provider bills your Medigap plan for the remaining approved amount.
4. Your Medigap plan pays its share based on your plan’s benefits.
5. You pay any remaining costs, such as deductibles, copays, or premiums not covered by Medigap.

Because Medigap policies are standardized, a Plan G from one company generally offers the same core benefits as a Plan G from another company, even though premiums may differ.

Types of Medigap Plans and How Coverage Varies

Each standardized Medigap plan is identified by a letter (A, B, C, D, F, G, K, L, M, N). The letter indicates which benefits are included, not the quality of the plan.

Some general patterns:

• Plan A
  • Basic coverage: typically includes Part A coinsurance, Part B coinsurance, first 3 pints of blood, and hospice coinsurance.
• Plans with broader coverage (such as some versions of F and G)
  • May cover Part A deductible, skilled nursing coinsurance, Part B excess charges, and foreign travel emergency.
• Cost‑sharing plans (like K and L)
  • Cover a percentage (not 100%) of certain services, often at lower premiums, but you pay more out of pocket when you get care.
• Plan N
  • Often includes many core benefits but may require copayments for some office visits and emergency room trips (under certain conditions).

The best way to know what your Medigap plan covers is to review:

• The “Summary of Benefits” or
• The outline of coverage from your insurer.

When Medigap Coverage Begins and How to Qualify

Your right to buy certain Medigap plans and the ease of getting coverage can depend on timing:

• During your Medigap Open Enrollment Period (usually the 6 months after you’re both 65 or older and enrolled in Part B), you generally have the widest access to Medigap plans in your area, often without medical underwriting.
• After that period, in many cases, companies may be allowed to use medical underwriting to decide whether to sell you a policy or what to charge, depending on your state and situation.

This timing doesn’t change what Medigap covers, but it can affect which plans you can get and what you pay.

Medigap vs. Medicare Advantage: Coverage Differences

It’s easy to mix up Medigap and Medicare Advantage (Part C), but they are very different:

• Medigap
  • Supplements Original Medicare (Part A and B)
  • Helps pay Medicare’s cost‑sharing (deductibles, coinsurance, copays)
  • Does not provide Part D drug coverage; does not replace Medicare
• Medicare Advantage
  • An alternative way to get your Medicare benefits through a private plan
  • Often includes built‑in networks, may include drug coverage and extra benefits not found in Medigap
  • You cannot use a Medigap policy with a Medicare Advantage plan

You typically choose one path or the other:

• Original Medicare + optional Medigap (and usually Part D), or
• A Medicare Advantage plan (which you cannot combine with Medigap).

Practical Questions People Often Have About Medigap Coverage

Does Medigap cover everything Medicare doesn’t?

No. Medigap is designed to help with cost‑sharing for Medicare‑covered services, not to fill every gap. It does not usually add major new categories of coverage such as dental, vision, or long‑term care.

Will Medigap pay if Medicare denies a claim?

Generally, if Medicare does not cover a service at all (for example, a non‑covered procedure), Medigap will not pay either. Medigap follows Medicare’s decisions on what’s covered.

Does Medigap cover preventive services?

Medicare covers many preventive services, and often you pay little or nothing for them under Part B. If there is a remaining coinsurance or copayment after Medicare pays, your Medigap plan may help pay that amount depending on the plan’s benefits.

Key Takeaways: What Is Covered in Medigap?

To pull it all together, here are the main points to remember:

• Medigap helps pay for Medicare’s “gaps”: deductibles, coinsurance, and copayments for Medicare‑covered hospital and medical services.
• Most Medigap plans cover:
  • Part A coinsurance and extra hospital days
  • Part B coinsurance or copayments (some fully, some partially)
  • First 3 pints of blood
  • Part A hospice coinsurance/copayments
• Many plans also cover:
  • Skilled nursing facility coinsurance
  • Part A deductible
  • Part B excess charges (only certain plans)
  • Limited foreign travel emergency coverage
• Medigap generally does not cover:
  • Prescription drugs
  • Routine dental, vision, and hearing services and devices
  • Long‑term custodial care or most non‑Medicare‑covered services
• Coverage details depend on the Medigap plan letter you choose and the policy options available in your state.

Understanding what is covered in Medigap can help you estimate your potential out‑of‑pocket costs with Original Medicare and decide whether a supplemental plan fits your situation and budget.