Short answer
Medigap is the supplement layer next to Original Medicare.
Medigap is private Medicare Supplement Insurance. Medicare.gov explains that it works with Original Medicare and can help pay some out-of-pocket costs, but it does not replace Medicare or work with Medicare Advantage.
Start here
What you actually came to find out
Plain answers first. Sources stay below for checking details.
What is it?
A private supplement policy used with Original Medicare.
What does it pay?
Some costs left by Original Medicare, depending on the policy.
What does it not do?
It does not work with Medicare Advantage, and it is not a Part D drug plan.
Where does it fit?
It belongs in monthly spending and bad-year health-cost risk.
Coverage structure
Original Medicare
Medicare.gov explains that Medigap works with Original Medicare.
Source trail: Medicare.gov
Plan boundary
Not Advantage
Medicare.gov says Medigap does not work with Medicare Advantage.
Source trail: Medicare.gov
Cost line
Premium
A Medigap policy adds a private premium to the Medicare budget.
Source trail: Medicare.gov, Medicare.gov
Travel layer
Possible
Medicare.gov notes that some Medigap policies may include foreign travel emergency benefits.
Source trail: Medicare.gov
The real planning question is whether a higher monthly premium buys enough cost predictability for the household health-care line.
Neutral landscape
The shape of the question
Medicare.gov is the main source because it defines Medigap and explains how it works with Original Medicare.
Source trail: Medicare.gov, Medicare.gov
The cost question comes next. Medicare.gov separates premiums, deductibles, copayments, and coinsurance, which is the budget vocabulary a Medigap page needs.
Source trail: Medicare.gov
The plan-choice boundary matters because Medicare.gov compares Original Medicare and Medicare Advantage as different coverage structures.
Source trail: Medicare.gov
Travel belongs in the health-care layer because Medicare.gov treats foreign care as a separate coverage question.
Source trail: Medicare.gov
Curator core
What the authorities say
These sources are here for the reader who wants to check the work. The plain-English answer stays above them.
Source 01
Medicare.gov
Medigap Basics
Medicare.gov explains Medicare Supplement Insurance, including the relationship between Original Medicare and Medigap policies.
Source framing
Medicare.gov frames Medigap as private insurance that helps pay some costs left by Original Medicare.
Strongest for: Medigap purpose and eligibility basics
Read at Medicare.govSource 02
Medicare.gov
How Medigap Works
Medicare.gov explains how Medigap works with Original Medicare, monthly premiums, and coverage boundaries.
Source framing
Medicare.gov explains that Medigap policies work with Original Medicare, not Medicare Advantage.
Strongest for: Medigap mechanics and plan-boundary rules
Read at Medicare.govSource 03
Medicare.gov
Compare Original Medicare and Medicare Advantage
Medicare.gov compares Original Medicare and Medicare Advantage across provider access, referrals, drug coverage, and supplemental coverage.
Source framing
Medicare.gov treats Original Medicare and Medicare Advantage as different coverage structures, not two names for the same thing.
Strongest for: Original Medicare versus Medicare Advantage comparison
Read at Medicare.govSource 04
Medicare.gov
Medicare Costs
Medicare.gov explains premiums, deductibles, copayments, coinsurance, and cost vocabulary.
Source framing
Medicare.gov is the consumer source for Medicare cost categories and premium terms.
Strongest for: Medicare cost vocabulary
Read at Medicare.govSource 05
Medicare.gov
Medicare & You 2026
The official Medicare handbook explains Medicare costs, coverage choices, annual updates, and where to check current premium amounts.
Source framing
Medicare & You is the official consumer handbook for Medicare coverage, costs, and annual plan choices.
Strongest for: consumer-facing Medicare context
Read at Medicare.govSource 06
Medicare.gov
Travel Outside the U.S.
Medicare.gov explains how Original Medicare usually treats care outside the United States and the narrow exceptions.
Source framing
Medicare.gov draws the travel boundary for care outside the United States.
Strongest for: Medicare coverage outside the U.S.
Read at Medicare.govPlain-English forks
The forks people face
Most retirement questions hide a few smaller decisions. These are the practical pieces that change the plan.
Original Medicare or Medicare Advantage?
Why it matters: Medigap only pairs with Original Medicare, so the first fork is coverage structure.
In real life: This fork changes networks, premium structure, and out-of-pocket risk.
What to look at: What to look at: Medicare.gov plan-comparison pages.
Monthly premium or more variable costs?
Why it matters: A supplement can raise the fixed monthly bill while lowering some surprise exposure.
In real life: This fork changes the spending floor.
What to look at: What to look at: the premium, deductible, and coinsurance line.
How much travel is in the plan?
Why it matters: Foreign travel can create a separate emergency-coverage question.
In real life: This fork changes the travel dream and health-risk layer.
What to look at: What to look at: Medigap foreign travel language and Medicare.gov travel boundaries.
Common questions
Quick answers
Short, plain answers for the questions people usually have next. The source trail stays available below.
Is Medigap the same as Medicare Advantage?+
No. Medicare.gov explains that Medigap works with Original Medicare and does not work with Medicare Advantage.
Does Medigap replace Medicare?+
No. It is private insurance that can help pay some costs after Original Medicare pays its share.
Does Medigap include drug coverage?+
Medigap is separate from Part D drug coverage, so prescriptions need their own plan check.
Why does Medigap matter for retirement spending?+
It can turn part of health care into a fixed monthly premium and change bad-year out-of-pocket risk.
Can Medigap help with foreign travel?+
Medicare.gov says some Medigap policies may cover foreign travel emergency care, depending on the policy.
Where does Medigap fit in the journey?+
It belongs in the health-cost line with Part B, drug coverage, travel, and expected out-of-pocket risk.
How this page is curated
This page uses Medicare.gov Medigap, plan-comparison, cost, and travel pages, plus the official Medicare & You handbook.
Read the planner methodologyTrust anchor
Sources used on this page
Every source named above is listed here in one place.
Medicare.gov. Medigap Basics
https://www.medicare.gov/health-drug-plans/medigap/basicsMedicare.gov. How Medigap Works
https://www.medicare.gov/health-drug-plans/medigap/basics/how-medigap-worksMedicare.gov. Compare Original Medicare and Medicare Advantage
https://www.medicare.gov/basics/get-started-with-medicare/get-more-coverage/your-coverage-options/compare-original-medicare-medicare-advantageMedicare.gov. Medicare Costs
https://www.medicare.gov/basics/costs/medicare-costsMedicare.gov. Medicare & You 2026
https://www.medicare.gov/publications/10050-medicare-and-you.pdfMedicare.gov. Travel Outside the U.S.
https://www.medicare.gov/coverage/travel-outside-the-u.s.
Before you act on this
This plan is educational. It is not personalized financial, tax, or insurance advice. Projections illustrate the math, they do not predict the future. Talk to your own licensed financial professional before acting on any of it.