Once I understood how much Original Medicare leaves uncovered — that uncapped 20% coinsurance I wrote about in my Part B cost breakdown — the next question was obvious: is a Medigap policy worth the extra premium? So I spent time digging into how Medigap actually works, what the lettered plans cover, and the enrollment timing rules that can make or break your options later.
What Medigap Actually Covers
Medigap policies are sold by private insurance companies, but the benefits are standardized by the federal government — not the insurer. That means a Plan G policy has to cover the exact same things no matter which company sells it. The plans are labeled with letters: A, B, D, G, K, L, M, and N are currently sold to new enrollees. (Plans C and F still exist, but only if you were eligible for Medicare before January 1, 2020 — new enrollees can no longer buy them.)
Every Medigap plan covers at least a portion of your Part A coinsurance and hospital costs. From there, the plans differ in how much of your Part B coinsurance, deductibles, and other gaps they pick up. Of the current options, Plan G is the most comprehensive — it covers everything except the Part B deductible. Plan N, by contrast, covers similarly broad benefits but requires small copays for some office visits and ER trips, which keeps its premium lower.
Plan G vs. Plan N: The Two Most Common Choices
For most people newly eligible for Medicare, the real decision usually comes down to Plan G or Plan N.
With Plan G, you cover your Part B coinsurance in full. No copays, no surprises, once you’ve met the annual Part B deductible ($283 in 2026). You pay a higher monthly premium in exchange for essentially never seeing another medical bill for Medicare-covered services.
Plan N carries a lower monthly premium. In exchange, you pay a small copay — typically up to $20 for many doctor visits and up to $50 for an ER visit that doesn’t result in admission. It also doesn’t cover the Part B excess charges some doctors are legally allowed to bill above what Medicare approves, which Plan G does cover.
Which one makes sense depends on how often you expect to use care. If you see doctors frequently, Plan G’s predictability often wins out. If you’re generally healthy and want to trim your monthly premium, Plan N can be the better trade.
How Medigap Pricing Actually Works
This is the part that surprised me most. It’s also the least understood piece of Medigap shopping: insurers price the exact same standardized plan differently based on how they structure premiums over time. There are three pricing models, and your state determines which ones are available to you.
Community-rated: Everyone with the same plan pays the same premium regardless of age. Premiums can still rise due to inflation and claims costs, but 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 increase just because you age. But someone who buys the same plan at 70 will pay more than someone who bought it at 65.
Attained-age-rated: Premiums increase as you age, similar to how term life insurance often works. These policies frequently start cheaper than the other two models but can become significantly more expensive over time.
Because two insurers can sell an identical Plan G with completely different long-term cost trajectories, comparing sticker prices alone can be misleading. It’s worth asking any insurer directly which pricing model they use before enrolling.
The Enrollment Timing Rule That Matters Most
Your Medigap Open Enrollment Period is a one-time, six-month window that starts the month you’re both 65 or older and enrolled in Part B. During this window, insurers in most states can’t deny you a policy, charge you more, or make you wait for coverage of a pre-existing condition. Your health history doesn’t factor in.
Outside that window, it’s a different story. In most states, insurers can use medical underwriting — meaning they can deny coverage, charge higher premiums, or exclude pre-existing conditions based on your health. A handful of situations trigger additional “guaranteed issue” rights outside your initial window, like losing employer coverage or a Medicare Advantage plan closing. Those are exceptions, not the rule.
This is also the timing issue I flagged in my Medicare coverage comparison guide: if you start on Medicare Advantage and later decide you want Original Medicare plus Medigap, you may face medical underwriting to get a Medigap policy at that point. It’s worth thinking through this before you make your initial enrollment choice, not after.
What Medigap Doesn’t Cover
Medigap fills gaps in Original Medicare, but it isn’t a catch-all. It doesn’t include:
Prescription drugs. You’ll need a separate Part D plan alongside any Medigap policy.
Dental, vision, and hearing. None of the standardized Medigap plans include routine coverage for these — a gap I went into in more detail in my healthcare planning notes.
Long-term custodial care. Medigap doesn’t cover the kind of ongoing custodial care that assisted living or nursing home stays often require.
It’s also worth remembering that Medigap only works alongside Original Medicare. You cannot have a Medigap policy and a Medicare Advantage plan at the same time — insurers aren’t permitted to sell you one if you’re enrolled in the other.
Frequently Asked Questions
How much does Medigap cost?
It varies significantly by your state, age, gender in some states, tobacco use, and the insurer’s pricing model. There isn’t one number I can give you here that would be accurate for your situation. Getting a few quotes for the same plan letter is the only reliable way to compare.
Can I switch Medigap plans later?
Yes, but outside your initial enrollment window or a guaranteed-issue situation, the new insurer can medically underwrite you, just like a first-time applicant.
Does Medigap cover the Part B premium?
No. You still pay your Part B premium (including any IRMAA surcharge) in addition to your Medigap premium. My IRMAA calculator can show you what that premium looks like based on your income.
Is Plan F still available?
Only to people who were eligible for Medicare before January 1, 2020. If you’re newly eligible, Plan G is the closest equivalent still on the market.
Do I need Medigap if I’m generally healthy?
It depends on your risk tolerance. Original Medicare’s 20% coinsurance has no annual cap, so even a healthy year can turn into a costly one after a single hospitalization or major procedure. Medigap is really about protecting against that uncapped exposure, not about how much care you use in a typical year.
Where to Go From Here
If you haven’t already, it’s worth reading through my 2026 Part B cost guide to understand the premium and IRMAA brackets Medigap sits on top of, and my Medicare coverage comparison guide if you’re still weighing Medigap against Medicare Advantage. My IRMAA calculator can estimate your Part B premium in a few seconds based on your income.
As always — I’m not a financial advisor or licensed insurance agent, just someone working through these decisions myself and sharing what I learn. Medigap pricing and plan availability vary by state. It’s worth a conversation with a licensed Medicare counselor or your local State Health Insurance Assistance Program (SHIP), which offers free, unbiased help comparing your specific options.