When people first enroll in Medicare, one of the most confusing questions is:

“What does Medicare cover, and what does a Medicare Supplement cover?”

Understanding how these two work together is essential to avoiding unexpected medical bills. In simple terms:

• Original Medicare pays for most of your healthcare

• A Medicare Supplement helps pay the costs Medicare leaves behind

Let’s break down exactly how this works.

What Original Medicare Covers

Original Medicare consists of two main parts:

Medicare Part A (Hospital Insurance)

Part A primarily covers inpatient care, including:

• Hospital stays

• Skilled nursing facility care after a hospital stay

• Hospice care

• Limited home health care

However, Part A still has deductibles and cost-sharing. For example, each hospital stay begins with a deductible before Medicare begins paying.

Medicare Part B (Medical Insurance)

Part B covers doctor and outpatient services, including:

• Doctor visits

• Specialist visits

• Lab work and diagnostic tests

• Imaging (CT scans, MRIs, X-rays)

• Preventive services

• Durable medical equipment

• Outpatient surgery

After you meet the annual Part B deductible, Medicare generally pays about 80% of the Medicare-approved amount, and you are responsible for the remaining 20%.

The Gap in Medicare Coverage

While Medicare covers a large portion of healthcare costs, it does not cover everything.

Some of the most important gaps include:

• The 20% coinsurance under Part B

• Hospital deductibles under Part A

• Skilled nursing coinsurance

• No limit on out-of-pocket costs

Because there is no annual out-of-pocket cap with Original Medicare, serious illness or hospitalization could result in significant medical bills.

This is where Medicare Supplement plans come in.

What a Medicare Supplement (Medigap) Covers

A Medicare Supplement plan, also known as Medigap, is designed to cover the gaps left behind by Original Medicare.

These plans work alongside Medicare to help pay for:

• Medicare deductibles

• The 20% coinsurance for doctor visits and outpatient services

• Hospital coinsurance

• Skilled nursing coinsurance

• Certain excess charges

Because Medicare remains the primary insurance, the supplement simply fills in the remaining portion of the bill.

How Medicare and a Supplement Work Together

The way the two plans work together is actually very simple.

Step 1: You receive medical care

You visit a doctor or hospital that accepts Medicare.

Step 2: Medicare pays first

Medicare reviews the claim and pays its portion (typically about 80%).

Step 3: Your supplement pays the rest

Your Medicare Supplement plan automatically covers the remaining costs depending on your plan type.

In many cases, this means little to no out-of-pocket cost for covered services.

Why Many People Choose a Medicare Supplement

Many beneficiaries choose a Medicare Supplement because it offers:

• Predictable healthcare costs: Most of the gaps in Medicare are covered.
• Freedom to choose doctors: You can see any doctor in the United States who accepts Medicare.
• No provider networks: Unlike many other insurance plans, there are no referrals required and no networks to stay within.
• Nationwide coverage: Your coverage follows you anywhere in the country as long as the provider accepts Medicare.

This flexibility is one of the biggest reasons Medicare Supplement plans remain popular among Medicare beneficiaries.

A Simple Example

Let’s say you visit a doctor and the Medicare-approved amount for the visit is $100.

With Medicare alone:

• Medicare pays about $80

• You pay the remaining $20

With a Medicare Supplement:

• Medicare pays $80

• Your supplement plan pays the remaining $20

Your out-of-pocket cost could be $0, depending on the plan you choose.

The Bottom Line

Original Medicare provides strong health coverage, but it leaves several important costs behind.

A Medicare Supplement plan works alongside Medicare to fill those gaps, helping protect you from unexpected medical bills while allowing you to keep the freedom to see any Medicare-accepting doctor nationwide.

For many beneficiaries, the combination of Medicare + a Supplement plan creates the most predictable and flexible coverage available.

✔ Have questions about Medicare or Medicare Supplement plans?
Our advisors can walk you through your options and help you find the coverage that fits your needs.