The Short Answer
A Medigap policy — also called a Medicare Supplement — is a separate insurance policy you buy from a private company that pays most or all of the costs Original Medicare leaves you owing: the 20% coinsurance, the hospital deductible, and more, depending on the plan. You keep Original Medicare exactly as it is — any doctor, any hospital, nationwide, no networks — and the Medigap policy just fills in behind it. The tradeoff is a higher monthly premium in exchange for costs that are far more predictable. It’s the other major path through Medicare, alongside Medicare Advantage, and the two are genuinely different products solving the same problem in opposite ways.
Key Takeaways
- Medigap doesn’t replace Medicare — it works alongside Original Medicare to pay the gaps.
- Plans are standardized by letter (A, B, D, G, K, L, M, N) — but in practice, Plan G and Plan N account for the vast majority of new enrollments, and several of the other letters are rarely chosen once the numbers are compared.
- Every insurer selling “Plan G,” for example, has to cover the exact same benefits — the only real differences between companies are premium, customer service, and financial strength.
- Medigap doesn’t include drug coverage — you’ll pair it with a separate Part D plan.
- Your best window to enroll without medical underwriting is your 6-month Medigap Open Enrollment Period, which starts the month you’re 65 and enrolled in Part B.
- Medigap and Medicare Advantage don’t work together — you pick one path or the other.
What a Medigap Policy Actually Does
Original Medicare covers a lot, but it doesn’t cover everything, and it doesn’t cap what you could owe in a bad year. After Medicare pays its share of a covered service, you’re typically responsible for 20% of the bill — with no ceiling on how high that 20% could add up if you have a serious illness or a long hospital stay.
A Medigap policy exists to close that gap. Depending on which lettered plan you choose, it can pay some or all of:
- The 20% coinsurance Original Medicare leaves you owing
- The Part A hospital deductible ($1,736 in 2026)
- Skilled nursing facility coinsurance
- The first three pints of blood, if you ever need a transfusion
- In some plans, a portion of the Part B deductible ($283 in 2026) — though this benefit is being phased out for anyone new to Medicare since 2020
Paul’s Honest Take: The easiest way I explain this to a client: Original Medicare is like a really good insurance policy with a 20% co-pay that never stops. Medigap is what takes that 20% off your plate. Once it’s in place, most people go years without ever seeing a real medical bill beyond their monthly premium.
Medigap vs. Medicare Advantage: The Distinction Almost Nobody Explains Well
If you’ve read our [Medicare Advantage guide], you’ve already seen this comparison from the other side. It’s worth repeating here, because this is the decision point that confuses more people than anything else in Medicare.
Path 1: Original Medicare + Medigap. You keep Original Medicare exactly as it is — nationwide access, no networks, no referrals — and layer a Medigap policy on top to cover the gaps. You pay a higher monthly premium for the privilege, but your costs at the doctor’s office or in the hospital become extremely predictable, often close to $0 depending on the plan. You’d add a standalone Part D plan alongside it for drug coverage.
Path 2: Medicare Advantage. You give up the “any doctor, anywhere” structure for a plan that usually includes drug coverage and extras like dental and vision, often with a low or $0 monthly premium. Your costs show up as copays when you use care, capped at a yearly maximum, but you don’t know the exact bill until after you’ve gotten care.
| Original Medicare + Medigap | Medicare Advantage | |
|---|---|---|
| Monthly premium | Higher — varies by plan and age, plus a separate Part D plan | Often $0–$50, plus your Part B premium |
| Doctor access | Any doctor or hospital in the U.S. that accepts Medicare | Limited to plan's network, usually within your service area |
| Referrals needed? | No | Often yes, for HMO plans |
| Drug coverage | Requires a separate Part D plan | Usually built in |
| Extra benefits (dental, vision, hearing) | Not included — buy separately if wanted | Usually included |
| Yearly cost cap | No hard cap, but costs are far more predictable month to month | Yes — $9,250 in-network max for 2026 |
| Cost when you actually get sick | Minimal to none, depending on your plan | Copays and coinsurance, up to your yearly max |
| Traveling out of state or abroad | Covered nationwide; some plans include limited foreign travel coverage | Usually limited or not covered outside your service area |
| Enrolling later without medical questions | Best window is a one-time 6-month period; after that, may require underwriting | Easier to get into anytime during an enrollment period |
Paul’s Honest Take: If I had to boil this down to one sentence: Medigap trades a higher monthly cost for predictability. Medicare Advantage trades predictability for a lower monthly cost. I’ve enrolled thousands of people in both, and the right answer depends on your health, your finances, and your personality. Some people sleep better knowing exactly what a hospital stay will cost before it happens — that’s who Medigap is really built for.
The Lettered Plans, Explained
Every Medigap plan is standardized by law, named with a letter. That standardization is actually one of the best consumer protections in all of Medicare: a Plan G from one company covers the exact same benefits as a Plan G from any other company, in the same state. The only things that differ between insurers are price, customer service, and financial stability.
The plans available today are: A, B, D, G, K, L, M, and N. (Plans C, F, and the high-deductible version of F are closed to anyone who became eligible for Medicare on or after January 1, 2020 — if you already have one of these, you can keep it, but new enrollees can’t buy them.)
The two plans almost everyone actually compares
Plan G is the most comprehensive plan available to anyone new to Medicare since 2020, and it’s become the most popular Medigap plan sold today. It covers everything except the Part B deductible ($283 in 2026) — you pay that once, out of pocket, and after that, Plan G covers your share of virtually everything else.
Plan N covers nearly as much as Plan G, but asks you to share a bit more of the cost in exchange for a noticeably lower premium: you pay small copays (up to $20 for a doctor visit, up to $50 for an ER visit that doesn’t result in admission), and you may be responsible for “excess charges” — the difference some doctors are legally allowed to charge above what Medicare approves, which Plan G covers in full and Plan N does not.
Paul’s Honest Take: Plan G vs. Plan N is the single most common comparison I run for clients, and it genuinely comes down to math. If the premium difference in your area is bigger than what you’d realistically pay in Plan N’s copays over a year, Plan N usually wins. If it’s close, most people prefer Plan G’s simplicity — no copay to think about, no excess charge to worry about, ever.
High-Deductible Plan G: the third option most people never hear about
There’s a lower-premium version of Plan G with a real tradeoff built in: High-Deductible Plan G. It pays the exact same benefits as standard Plan G, but only after you’ve paid $2,950 out of pocket yourself in a calendar year (2026 figure, adjusted annually — this includes your Part B deductible). Once you hit that number, it covers 100% of your Medicare-approved costs for the rest of the year, just like standard Plan G does from day one.
Paul’s Honest Take: High-Deductible Plan G is one of the most underused plans in Medicare, and it’s the one I recommend most often when I genuinely believe it’s the right fit — even though it pays me a lower commission than standard Plan G. I say that on purpose: if I’m recommending a plan that earns me less, you know it’s about what’s right for you, not what’s right for my paycheck. For someone in reasonably good health who wants real protection against a catastrophic year without paying a high premium every single month for coverage they may barely use, the math on High-Deductible Plan G can be excellent.
The other standardized plans, briefly
- Plan A — the most basic level of coverage, covering the core benefits only. Rarely the best value once you compare total costs.
- Plan B — Plan A’s benefits plus the Part A deductible.
- Plan D — Broad coverage similar to Plan G, but without the Part B excess charge protection.
- Plan K and Plan L — Lower premiums in exchange for cost-sharing on most benefits, with an annual out-of-pocket limit that caps your worst-case year.
- Plan M — Covers half the Part A deductible, no Part B deductible coverage.
For most people shopping today, the real decision is almost always between Plan G, Plan N, and High-Deductible Plan G — the rest exist, but rarely come out ahead once you run the numbers.
The Plans Almost Nobody Actually Buys
It’s worth saying plainly: Plan G and Plan N account for the overwhelming majority of new Medigap enrollments today, and High-Deductible Plan G has been steadily gaining ground behind them. Plans A, B, D, K, L, and M still technically exist and are still sold in most states, but very few people newly shopping Medigap actually end up choosing them — the coverage-to-premium math on Plan G or Plan N almost always comes out ahead. If an agent is showing you one of these lesser-used letters, it’s worth asking directly why, compared to Plan G or Plan N, for your specific situation.
Why Doctors and Hospitals Tend to Prefer Medigap Patients
This doesn’t get talked about much, but it’s real, and it’s worth knowing: many doctors and hospitals genuinely prefer treating patients on Original Medicare with a Medigap policy over patients on Medicare Advantage. A few honest reasons why:
- No prior authorization hassle. Original Medicare rarely requires a provider to get advance approval before performing a service. Medicare Advantage plans frequently do, which means more paperwork, more delays, and more denied or reduced claims for the provider’s office to fight.
- Simpler, faster claims. Billing Original Medicare is a well-worn, predictable process. Billing dozens of different Medicare Advantage plans, each with its own rules, is genuinely more administrative work for a practice.
- Providers are typically paid Medicare’s standard rate promptly, without the extra negotiation, documentation, or appeals that can come with a Medicare Advantage claim.
Paul’s Honest Take: I’ve had more than one doctor’s office tell a client, off the record, that they simply prefer seeing Original Medicare patients. That’s not a knock on Medicare Advantage — plenty of practices handle it well — but it’s a real, practical reason some people find their appointments easier to book and their care less encumbered by paperwork once they’re on Original Medicare with a Medigap policy behind it.
Medigap Doesn’t Include Drug Coverage
This trips people up constantly: a Medigap policy does not include prescription drug coverage. If you go the Medigap route, you’ll need to separately enroll in a standalone Part D plan to cover your medications. It’s an extra decision and an extra monthly premium, but it also means you can pick the Part D plan that best matches your specific medications, rather than being stuck with whatever drug formulary comes bundled into a Medicare Advantage plan.
When to Enroll: The Window That Matters Most
Here’s the single most important timing rule in this entire guide: your Medigap Open Enrollment Period is a 6-month window that starts the month you’re both 65 or older and enrolled in Part B. During this window, insurance companies have to sell you any Medigap policy they offer, at their best available rate, regardless of your health history. No medical questions, no denials, no charging you more because of a pre-existing condition.
Miss that window, and it’s a different story. Outside of it, insurers in most states are allowed to ask health questions, charge you more, or deny you coverage entirely based on your medical history — unless you qualify for a guaranteed issue right, which applies in specific situations like losing employer coverage or a Medicare Advantage plan leaving your area.
Paul’s Honest Take: This is the single biggest Medigap mistake I see, and it’s almost always avoidable. Someone enrolls in Medicare Advantage at 65, decides five years later they want to switch to Medigap, and discovers they now have to answer health questions — and depending on what’s changed with their health, they might get a higher rate or even get turned down. If there’s any chance you might want Medigap down the road, it’s worth having that conversation before your Open Enrollment window closes, not after.
You Can Apply to Switch Medigap Plans Any Month — But That Doesn’t Mean You’ll Get Approved
This is a distinction that trips people up: you can apply to switch your Medigap policy in any month of the year. There’s no calendar restriction on when you’re allowed to submit an application. What most states don’t guarantee, outside of your original Open Enrollment window or a qualifying guaranteed issue event, is that you’ll actually be approved.
In most states, once you’re outside those protected windows, the new insurer is legally allowed to ask health questions and can decline your application or charge you a higher rate based on your health history. So “I can switch anytime” and “I’m guaranteed to get the new plan” are two different things — and it’s the second one that actually matters.
The Birthday Rule: A Growing List of Exceptions
There’s an important, and fairly recent, wrinkle to this: a growing number of states have passed their own Medigap Birthday Rule — a state-level law that gives existing Medigap policyholders a short annual window, tied to their birthday, to switch to a different plan or carrier without medical underwriting, even outside their original enrollment window.
Here’s how it generally works where it exists: for a set number of days around your birthday each year — commonly 30 to 63 days, depending on the state — you can apply to switch to a Medigap plan with equal or lesser benefits, and the new insurer has to accept you at their standard rate, no health questions asked. Some states restrict you to switching within your current insurance company; others let you move to any carrier. The exact window length and rules vary meaningfully state to state.
As of 2026, the birthday rule has been adopted in a growing list of states, including California, Idaho, Illinois, Kentucky, Louisiana, Maryland, Nevada, Oklahoma, Oregon, Rhode Island, Utah, Virginia, Wyoming, and — newly added for 2026 — Delaware, Indiana, and West Virginia. New Mexico’s version is set to take effect January 1, 2027. A handful of other states, including New York, Connecticut, Maine, and Massachusetts, take a different approach and offer broader year-round guaranteed-issue protections instead of a birthday-specific window.
Paul’s Honest Take: This is one of the fastest-moving parts of Medigap right now — new states are adding birthday rules almost every legislative session, and the details genuinely differ from state to state: window length, which carriers you can move to, whether you need the same plan letter or just “equal or lesser” benefits. If you’re in a birthday rule state, this can be a real opportunity to shop your premium down every single year without medical underwriting — but only if you actually know your window and use it. I check this for every Medigap client I have, every year, because most people have no idea the option exists.
How Medigap Premiums Are Priced
Medigap premiums aren’t priced the same way everywhere, and this matters more than most people realize. Insurers use one of three rating methods:
- Community-rated: Everyone pays the same premium regardless of age. Premiums only rise due to inflation or claims experience, not because you got older.
- Issue-age-rated: Your premium is locked in based on your age when you first bought the policy — it won’t go up just because you get older, though it can still rise due to inflation.
- Attained-age-rated: Your premium is based on your current age, and increases as you age, in addition to any inflation-related increases.
Paul’s Honest Take: Two people can buy the exact same Plan G and end up on very different pricing trajectories over 15 years, depending purely on which rating method their state and carrier use. This is exactly the kind of thing I check before recommending a specific company — not just today’s premium, but how it’s likely to move over time.
Premiums Have Been Rising Faster Than People Expect — Especially Since COVID
Medigap has always carried a higher monthly premium than Medicare Advantage in exchange for its predictability. What’s changed more recently is the pace those premiums have been climbing. Since the pandemic, Medigap carriers across the board have pushed through noticeably larger annual rate increases than the years before it — driven by higher medical costs, rising utilization, and inflation working through the healthcare system generally.
Paul’s Honest Take: This is exactly why I don’t just enroll a client in a Medigap plan and disappear. A rate that’s competitive today can be one of the pricier options in three or four years, especially with an attained-age-rated carrier. I review my clients’ Medigap premiums regularly — not just at enrollment — because “set it and forget it” isn’t really a safe strategy with this kind of coverage anymore.
Original Medicare Is Getting Its Own Prior Authorization Pilot
One more thing worth knowing, because it’s new and it’s genuinely changing the landscape: for years, one of Original Medicare’s biggest selling points over Medicare Advantage has been that it rarely requires prior authorization before you get care. That’s starting to shift. CMS has launched a pilot program — called the WISeR Model — that requires prior authorization or pre-payment review for a specific list of outpatient services under Original Medicare, currently running in six states: Arizona, New Jersey, Ohio, Oklahoma, Texas, and Washington, for services delivered from January 2026 through 2031.
This pilot only applies to a defined list of about 17 outpatient services (things like certain nerve stimulators, skin substitutes, and specific pain-management injections) — it does not touch routine visits, hospital stays, or most of what a typical Medigap client experiences day to day. But it’s a real shift worth watching: if the pilot expands, more of Original Medicare could eventually look a little more like the prior-authorization process people associate with Medicare Advantage today.
Paul’s Honest Take: I bring this up with clients not to scare anyone — this pilot is narrow, and it doesn’t apply outside these six states right now. But “Original Medicare never requires prior authorization” has been one of the strongest arguments for Medigap for years, and it’s not quite as absolute a statement as it used to be. I’ll keep watching this one closely and update clients if it expands.
Who Medigap Tends to Fit Well
- You want the freedom to see any doctor or specialist in the country, anytime, without a referral
- Predictable monthly costs matter more to you than the lowest possible premium
- You travel frequently, split time between two states, or spend part of the year outside your home area
- You have a chronic or serious health condition where minimizing surprise costs matters
- You’re within your 6-month Medigap Open Enrollment window and want to lock in coverage without medical underwriting
Who Should Take a Harder Look at the Alternative
- Keeping your monthly premium as low as possible is the top priority
- You’d like dental, vision, and hearing coverage bundled into one plan
- You’re comfortable with a network of doctors and occasional referrals
- You’re generally healthy and comfortable with some unpredictability in exchange for lower fixed costs
Frequently Asked Questions
The Bottom Line
Medigap isn’t the “expensive” option and Medicare Advantage isn’t the “cheap” one — they’re two different philosophies for handling the same gap in Original Medicare, and the right one depends on how you value predictability versus a lower monthly cost. If freedom to see any doctor, anywhere, without a referral, and knowing almost exactly what a bad health year will cost you matters most, Medigap is very likely worth the higher premium. If keeping your monthly cost low matters more and you’re comfortable with a network, Medicare Advantage may make more sense.
If you want to run the actual numbers for your situation — comparing specific Medigap carriers, or comparing Medigap against Medicare Advantage side by side — that’s exactly the conversation I have with clients every day, at no cost to you. I represent 40+ carriers, so there’s no company I’m pushed to recommend over another.
Call 631-358-5793 or visit paulbinsurance.com to set up a time to talk it through.
Paul Barrett, CMIP, is the founder of The Modern Medicare Agency and has spent 18+ years exclusively helping people navigate Medicare — never life insurance, never annuities, just Medicare. He’s licensed in 37 states, represents more than 40 carriers, and has personally helped over 5,000 clients choose coverage that actually fits their lives.
Figures current as of 2026 and sourced from CMS. Medigap availability, pricing, and rating methods vary by state — always verify specific plan rates for your state before enrolling.
