Medicare Supplement Insurance (Medigap): What It Is, How It Works, and What to Consider

Original Medicare is a strong foundation — but it doesn't cover everything. After Medicare pays its share of your hospital and medical bills, you may still owe deductibles, coinsurance, and copayments that can add up quickly. That's exactly what Medicare Supplement insurance, commonly called Medigap, is designed to help with.

If you've been hearing the terms "Medicare Supplement" and "Medigap" and aren't sure what they mean or whether one might make sense for you, you're in the right place. This guide explains how Medigap works, what the different plans cover, when to enroll, and what to think about before making a decision.

What Is Medicare Supplement Insurance (Medigap)?

Medicare Supplement insurance — also known as Medigap — is a type of private health insurance that works alongside Original Medicare (Part A and Part B). It helps pay for some of the out-of-pocket costs that Original Medicare leaves behind, such as deductibles, coinsurance, and copayments.

To be clear about what Medigap is and isn't:

• It is not a replacement for Original Medicare.
• It is not the same as Medicare Advantage (Part C).
• It works with Original Medicare, filling in some of the gaps in coverage.
• It is sold by private insurance companies, but the plans themselves are standardized by the federal government.

Medigap plans sold after 2005 do not include prescription drug coverage, so if you want drug coverage, you would need to enroll in a separate Medicare Part D prescription drug plan.

How Does Medigap Work?

When you have Original Medicare and a Medigap policy, the two work together. Original Medicare pays its share of your covered healthcare costs first. Then your Medigap plan steps in and pays some or all of the remaining costs, depending on the plan you have.

For example, Original Medicare Part A (hospital insurance) has a deductible for each hospital benefit period. Part B (medical insurance) has a yearly deductible. After those deductibles, you may still owe 20% coinsurance for Part B services — and with Original Medicare alone, there is no out-of-pocket maximum to limit your total exposure. A Medigap policy can help reduce or eliminate many of these costs.

One of the practical benefits of Medigap is that it gives you more predictable healthcare costs. When you know roughly what you'll pay each month in premiums and what your coverage looks like, it can be easier to plan and budget for healthcare expenses.

Medigap Plans Are Standardized — Here's What That Means

One of the most reassuring things about Medigap is that the plans are standardized. This means that the benefits for any given plan letter are identical regardless of which insurance company sells it. Plan G from one insurer covers the same things as Plan G from another insurer.

What can differ between insurers is the monthly premium you pay. Premiums vary based on factors such as the insurance company, your state, your age, and whether you use tobacco. This is why it can be worth comparing options rather than simply choosing the first plan you see.

Medigap plans are identified by letters: A, B, D, G, K, L, M, and N are the plans currently available to most new enrollees. Plans C and F, which offered slightly more comprehensive coverage, are no longer available to people who became eligible for Medicare on or after January 1, 2020.

For most new enrollees today, Plan G is the most comprehensive option available, covering nearly all gaps in Original Medicare except the Part B annual deductible, which is $283 in 2026. Plan N is another popular option that offers lower monthly premiums in exchange for small copayments for some office and emergency room visits.

What Does Medigap Typically Cover?

Coverage varies by plan letter, but Medigap plans may help pay for some or all of the following (depending on the specific plan):

• Medicare Part A coinsurance and hospital costs
• Medicare Part A deductible
• Medicare Part A hospice care coinsurance or copayment
• Medicare Part B coinsurance or copayment (the 20% you owe after Original Medicare pays)
• Medicare Part B excess charges in some cases
• Skilled nursing facility care coinsurance
• The first three pints of blood per year
• Foreign travel emergency care (up to plan limits, for select plans)

Medigap does not cover everything. It generally does not cover:

• Prescription drugs (you would need a separate Part D plan)
• Long-term care
• Vision or dental care
• Hearing aids
• Private-duty nursing

Medigap vs. Medicare Advantage: Understanding the Difference

This is one of the most common questions people have when they start exploring Medicare: What's the difference between Medigap and Medicare Advantage?

They are two very different approaches to covering your healthcare under Medicare:

Original Medicare + Medigap (+ Part D for drugs):

• You keep Original Medicare and use any doctor or hospital that accepts Medicare — no networks.
• Your Medigap policy helps cover the out-of-pocket costs Original Medicare doesn't pay.
• You add a separate Part D plan if you want prescription drug coverage.
• Your monthly costs are more predictable, though your combined premium may be higher.

Medicare Advantage (Part C):

• A private insurance company delivers your Medicare benefits all in one plan.
• Plans often include drug coverage and may offer additional benefits.
• Most plans have provider networks, meaning you may need to use specific doctors and hospitals.
• Out-of-pocket costs vary by plan.

An important note: you cannot use Medigap alongside a Medicare Advantage plan. Medigap works only with Original Medicare. If you have Medicare Advantage, a Medigap policy would not provide meaningful benefits.

Neither approach is universally better — the right choice depends on your health needs, your doctors, your medications, your budget, and your personal preferences. This is one of the reasons why speaking with a knowledgeable Medicare professional can be so helpful.

When Can You Enroll in Medigap?

The best time to enroll in a Medigap policy is during your Medigap Open Enrollment Period. This is a six-month window that starts the first month you have Medicare Part B and you are 65 or older.

During this period, insurance companies cannot refuse to sell you a Medigap policy, cannot charge you more based on pre-existing health conditions, and cannot make you wait for coverage (except for conditions related to a pre-existing health issue). This is your strongest consumer protection when it comes to Medigap.

This is a one-time period — it does not repeat every year the way the Medicare Annual Enrollment Period does. After it ends, insurance companies may use medical underwriting in most states, which means they can consider your health history when deciding whether to sell you a policy and how much to charge.

Some states provide additional Medigap enrollment rights. Your state's insurance department can tell you what protections are available where you live.

A Few Practical Things to Keep in Mind

If you are exploring Medigap, here are a few things worth knowing before you make any decisions:

Premiums vary — comparison shopping matters. Because the benefits for each plan letter are standardized, the main variable is the monthly premium. The same Plan G can vary significantly in price from one insurance company to another in the same area. Comparing quotes can help you find the most cost-effective option for the same coverage.

Medigap policies cover one person. These are individual policies. If you and your spouse both want Medigap coverage, you would each need your own separate policy.

Timing matters. Enrolling during your Medigap Open Enrollment Period gives you the broadest access to plans and the best pricing protections. Waiting until after that window may limit your options depending on your health and your state's rules.

Plans don't include drug coverage. If you go the Original Medicare + Medigap route, don't forget to also enroll in a Medicare Part D prescription drug plan if you take prescription medications. Missing the Part D enrollment window can result in a late enrollment penalty.

Your plan can generally not be canceled. As long as you pay your premiums, a Medigap insurer generally cannot cancel your policy because of your age, health status, or the number of claims you make.

Is Medigap Right for You?

Whether Medigap makes sense depends on your individual situation. Some people value the freedom to see any Medicare-accepting provider with predictable costs. Others prefer the all-in-one convenience of Medicare Advantage. Some people have other coverage — through a former employer, union, or government program — that changes the equation entirely.

There's no single right answer, and the decision you make when you first enroll can affect your options down the road. That's why it's worth taking the time to understand your choices before you decide — and to consider getting personalized guidance from a qualified Medicare professional.

For authoritative information about Medigap plans, you can visit Medicare.gov, where the federal government publishes a free guide called Choosing a Medigap Policy.

Questions About Medigap? We're Here to Help.

At Accessible Health & Wellness Solutions, we help individuals and families understand Medicare and their coverage options — clearly, honestly, and without pressure. Whether you're approaching 65 for the first time, reviewing your current coverage, or helping a parent navigate their Medicare decisions, we're happy to walk you through your options.

Schedule a free Medicare consultation with our team today. There's no cost, no obligation — just straightforward Medicare education tailored to your situation.