How Medigap works with Original Medicare
Medicare Supplement Insurance — usually called Medigap — is not a replacement for Medicare. It sits beside Original Medicare (Part A and Part B) and helps pay some of the costs that Original Medicare leaves to you.
- You receive Medicare-covered care. Your doctor or hospital sends the claim to Medicare.
- Original Medicare pays first. Medicare pays its approved share of the covered service.
- Your Medigap policy pays second. Depending on the plan letter, it pays some or most of the remaining Medicare-approved deductibles, coinsurance or copayments.
- You usually add Part D separately. Modern Medigap plans do not include outpatient prescription drug coverage, so people who want drug coverage generally enroll in a separate Part D plan.
Three Medigap choices we are often asked about
| Plan | How it generally works | What you still pay |
|---|---|---|
| Plan G | One of the most comprehensive options available to people newly eligible for Medicare. After you meet the annual Part B deductible, Plan G generally covers the remaining Medicare-approved Part A and Part B cost sharing covered by the policy, including Part B excess charges. | Your Medigap premium, the annual Part B deductible, Part D costs, and services Original Medicare does not cover. |
| Plan N | Provides broad coverage like Plan G but trades some first-dollar predictability for what is often a lower premium. Plan N pays Part B coinsurance, but you may owe up to a $20 copayment for certain office visits and up to $50 for certain emergency-room visits that do not result in an inpatient admission. | Your Medigap premium, the Part B deductible, the Plan N office/ER copays when applicable, and Part B excess charges because Plan N does not cover them. |
| High-Deductible Plan G | Uses the same standardized Plan G benefit structure, but the policy does not begin paying until you have paid a much larger annual amount of Medicare-covered deductibles, copayments and coinsurance. In 2026 the high-deductible amount is $2,950. This option often has a substantially lower monthly premium than standard Plan G. | Your premium plus Medicare-covered cost sharing until the high-deductible amount is met. The ordinary Part B deductible counts toward that high-deductible amount but is not itself paid by Plan G. |
What is a Part B excess charge?
Most doctors who accept Medicare also accept Medicare assignment, which means they agree to the Medicare-approved amount as full payment. A provider who accepts Medicare but does not accept assignment may, where allowed, charge above the Medicare-approved amount up to Medicare's permitted limit. Plan G covers Part B excess charges; Plan N does not. This issue is less common than ordinary coinsurance, but it is worth understanding when comparing the two plans.
Plan G vs. Plan N vs. High-Deductible G: what should you think about?
Your one-time 6-month Medigap Open Enrollment Period
Under federal law, your Medigap Open Enrollment Period lasts six months and begins the first month you're 65 or older and enrolled in Part B. During this period, you can buy any Medigap policy sold to you in your state without being denied because of pre-existing health problems.
Standardized benefits make comparison easier
In most states, Medigap plans with the same letter provide the same standardized basic benefits regardless of company. For example, one company's Plan G has the same standardized medical benefits as another company's Plan G. The insurer, premium, pricing method, customer service and rate history can still differ.
What Medigap generally does not include
Can you switch later?
Sometimes, but don't assume you can always move freely from one Medigap company or plan to another. Outside protected enrollment situations, medical underwriting may apply. Never cancel an existing Medigap policy until replacement coverage is approved and effective.
Official references: Medicare — Medigap basics and When can I buy Medigap?
Still have questions?
Medicare is personal. If you want help understanding how these rules fit your situation, Mike & Tracy can walk through it with you. There is no additional cost for our assistance.