Introduction
Medigap and Medicare Supplement Insurance are two names for the same thing: private insurance policies that help pay the out-of-pocket costs Original Medicare leaves behind, including deductibles and the standard 20% Part B coinsurance.
Many beneficiaries struggle with those leftover costs, then assume every Medigap plan fills the gaps the same way. They don't. Lettered plans differ substantially in premiums, cost-sharing, and what they cover. Enrolling at the wrong time can affect whether you get coverage at all, or how much you pay for it.
This guide breaks down how Medigap works, compares the main plan types side by side, clarifies which plans have been discontinued for new buyers, and gives you a framework for choosing coverage that fits your budget and health needs.
Key Takeaways
- Medigap pairs with Original Medicare Parts A and B — it generally cannot be combined with a Medicare Advantage plan.
- Benefits are standardized by plan letter in most states, but premiums and availability vary by insurer and location.
- Plans G and N suit many newly eligible beneficiaries; Plans F and C are largely limited to those eligible before 2020.
- Medigap doesn't include prescription drug coverage, so Part D needs separate evaluation.
- The best plan depends on your expected healthcare use, budget, provider preferences, and travel habits.
What Is Medigap and Why Does It Matter?
What Is Medicare Supplement Insurance?
Medigap is private insurance that helps pay certain Medicare-approved cost sharing, such as deductibles, coinsurance, and copayments. It doesn't replace Original Medicare. It works alongside it.
Here's how a claim typically flows:
- Original Medicare pays first for covered services, based on the Medicare-approved amount.
- Your Medigap policy pays its share of the remaining covered costs, according to your specific plan's benefits.
- You pay any leftover amount not covered by either, plus your monthly Medigap premium.
To buy a Medigap policy, you generally need both Medicare Part A and Part B. Medigap is designed to fill gaps in Original Medicare, not stand alone as your only coverage.
Why Does Medigap Matter?
Medigap makes healthcare expenses more predictable. Instead of facing variable coinsurance bills after a hospital stay or a string of specialist visits, you pay a set monthly premium and let the policy absorb much of the cost sharing.
Here's how it compares with the other common path:
- Medigap preserves your access to any provider who accepts Original Medicare, nationwide.
- Medicare Advantage is a different path entirely: a private plan that replaces Original Medicare and typically uses provider networks.
You can't have both at the same time.
Medigap also has real limits. According to CMS's official Medicare Supplement Insurance guide, Medigap policies generally don't cover prescription drugs, routine dental care, hearing aids, routine vision care, or long-term care.
Some insurers offer limited extras or discounts, but confirm specifics on Medicare.gov and in your policy documents before assuming anything is included.
Types of Medigap Plans
Most states use the federal standardized system, with plan letters A, B, D, G, K, L, M, N, plus F and C for those still eligible to buy them. Massachusetts, Minnesota, and Wisconsin use different standardized systems, so residents there should check their state's rules separately.
Here's the key concept to remember: the letter describes the benefits, not the insurance company. Plan G from one insurer covers the same standardized benefits as Plan G from another. What differs is the premium, the pricing method, and availability in your area.
Comprehensive or Higher-Coverage Options
Plan G is currently one of the most popular choices for people newly eligible for Medicare. It covers nearly all Part A and Part B cost sharing, with one exception: you pay the Part B deductible yourself, which is $283 in 2026.
Plan F is the most comprehensive standardized option, covering everything Plan G does plus the Part B deductible. The catch: Plan F is generally only available if you became eligible for Medicare before January 1, 2020. If you're already on Plan F, you can typically keep it.
Both plans also come in high-deductible versions in some states. You pay a lower premium, then cover $2,950 in 2026 in qualifying out-of-pocket costs before benefits kick in. Premiums do not count toward that deductible.
| Benefit | Standard Plan F | Standard Plan G |
|---|---|---|
| Part A deductible & skilled nursing coinsurance | Covered | Covered |
| Part B coinsurance & excess charges | Covered | Covered |
| Part B deductible | Covered | Not covered |
| Foreign travel emergency (plan limits apply) | 80% | 80% |
Moderate-Premium Options With Cost Sharing
Plan N offers a lower premium in exchange for some cost sharing. You'll typically pay:
- Up to $20 for some office visits
- Up to $50 for emergency room visits that don't result in inpatient admission
Plan N also doesn't cover Part B excess charges — an extra amount some providers can legally bill above the Medicare-approved rate.
Plans B, D, and M sit in this middle tier with different benefit mixes:
- Plan D: Covers the Part A deductible in full, plus skilled nursing coinsurance and foreign travel emergencies (plan limits apply)
- Plan M: Covers 50% of the Part A deductible, with a different mix of the remaining benefits
- Plan B: Covers a narrower combination focused on core Part A cost sharing
Because the exact mix varies, confirm details on the current official Medicare comparison chart. If you want a lower premium and can handle modest copays—and excess charges are uncommon with your doctors—Plan N is often the practical middle path.
Partial-Coverage and Lower-Premium Options
Plans K and L work differently. Instead of covering a fixed benefit, they pay a percentage of eligible costs until you hit an annual out-of-pocket limit:
| Plan | Share of covered costs paid | 2026 annual out-of-pocket limit |
|---|---|---|
| K | 50% | $8,000 |
| L | 75% | $4,000 |
Once you hit that limit and pay the annual Part B deductible, the plan covers 100% of covered services for the rest of the year. Run a quick estimate of your expected visits and hospital risk before picking K or L on premium alone.
Medicare SELECT is another route to lower premiums — it's a Medigap policy with a network condition attached, generally requiring you to use specific hospitals (and sometimes specific doctors) for full benefits. Verify network requirements carefully before enrolling.
Plans No Longer Available to Many New Beneficiaries
Under federal rules, Plans C and F generally can't be newly purchased if you became eligible for Medicare on or after January 1, 2020, because both cover the Part B deductible. If you were eligible before that date, you may still be able to buy one.
Older plan types — E, H, I, and J — stopped being sold to new applicants in 2010, though state timelines varied slightly.
Existing policyholders are not forced to drop coverage. If you already have a C, F, or older-letter plan, you can typically keep it. Confirm your rights on Medicare.gov, with your state insurance department, or with a licensed Medigap advisor who can also check current plan availability in your area.
How to Choose and Compare a Plan
How to Choose the Right Plan
Start by deciding how you want to balance monthly premiums against point-of-care costs. Comprehensive plans like F and G cost more upfront but leave little to pay later. Cost-sharing plans like N, K, and L lower your premium but ask you to shoulder more when you actually use care.
From there, work through these factors:
- Healthcare needs — frequent specialist visits, ongoing treatments, or planned procedures favor more comprehensive coverage.
- Travel habits — if you spend time outside the U.S., check foreign travel emergency benefits closely.
- Provider preferences — Original Medicare gives you access to any Medicare-participating provider; Medicare SELECT may restrict that.
- Prescription drugs — Medigap doesn't cover them. Review your medications, preferred pharmacies, and Part D formularies separately, and pay attention to enrollment timing.
- Premium comparison — the same plan letter can cost noticeably different amounts depending on the insurer.
According to KFF's 2024 analysis of Medigap enrollment, average monthly premiums among existing policyholders were $274 for Plan F versus $164 for Plan G in 2023. Your personal quote will still vary by age, location, tobacco use, and insurer.
Comparing those tradeoffs is easier with personalized help. Wareheim Medicare Advisors, based in Seminole, Florida, offers no-cost plan comparisons and annual reviews. Agents are licensed in Florida, Georgia, North Carolina, Nevada, and South Carolina, and weigh your health needs, budget, and provider preferences against the available options.
What to Check Before Finalizing a Plan
Before you apply or switch, confirm a few things:
- Your Medigap open enrollment window. This one-time, six-month protected period starts the month you turn 65 and enroll in Part B. During it, insurers can't deny you coverage or charge more due to health problems.
- Whether medical underwriting applies. Outside your protected window or a guaranteed-issue situation, insurers may ask health questions, decline coverage, or charge higher premiums, subject to state law.
- Total expected costs, not just the sticker price. A plan with a low starting premium can still cost more over a year of care than a slightly pricier one with broader coverage.
- Every detail in the official policy documents — deductibles, copayments, exclusions, and foreign travel provisions — rather than relying on informal summaries.
Conclusion
Medigap plan letters are standardized ways of covering Original Medicare's cost-sharing. The insurer you choose and the state you live in still shape your premium, availability, and enrollment rules.
Plans G, N, F, K, and L each serve a different combination of coverage needs, monthly budgets, and comfort with cost sharing. None of them is universally "best."
Compare current official benefits and your enrollment rights before you apply or switch. Individualized guidance often prevents an expensive mistake, and Wareheim Medicare Advisors offers no-cost plan comparisons to help you match a letter to your care needs and budget.
Frequently Asked Questions
What is the most expensive Medicare Supplement plan?
Premiums vary by insurer, location, age, and tobacco status, so there's no single answer. Plan F is historically among the most comprehensive, which often makes it pricier, but get current local quotes to compare.
Which is better, Medicare Supplement Plan F or G?
Plan F covers the Part B deductible; Plan G doesn't, but usually costs less. Plan F is also limited to people eligible for Medicare before 2020. The better choice depends on your eligibility, budget, and expected healthcare use.
Why is Plan G better than an Advantage plan?
It isn't automatically better. Plan G suits people who value nationwide provider access and predictable cost sharing. Medicare Advantage can offer bundled benefits and lower premiums, but with networks and different cost-sharing rules.
What are the top 3 Medigap plans?
Plans G, N, and F are the most commonly discussed. Popularity doesn't mean any one is right for everyone, and Plan F availability depends on when you became eligible for Medicare.
Which Medigap plans are no longer available?
Plans C and F generally can't be newly sold to people first eligible for Medicare on or after January 1, 2020. Older plans E, H, I, and J stopped being sold to new applicants in 2010.
Does Medigap cover dental or vision?
No. Standardized Medigap benefits typically exclude routine dental and vision care. Some insurers offer limited extras or discounts, so review your policy documents and consider a standalone plan if needed.
