Turning 65 brings a milestone many Americans greet with both relief and confusion: Medicare eligibility. While Original Medicare covers a substantial share of your healthcare costs, it leaves significant gaps — deductibles, copayments, coinsurance, and the 20% coinsurance on outpatient services that has no annual out-of-pocket cap. This is where Medicare Supplement plans, commonly called Medigap, come in. In 2026, more than 14 million Americans rely on Medigap policies to fill those gaps and protect their retirement savings from unpredictable medical bills.
This comprehensive guide explains what Medigap plans cover, how the standardized Medicare plans compare, what they cost in 2026, and how to choose the right plan during your enrollment window.
What Is a Medicare Supplement (Medigap) Plan?
A Medicare Supplement plan is private health insurance sold by insurance companies to fill the "gaps" in Original Medicare (Part A hospital insurance and Part B medical insurance). Medigap does not replace Medicare — it works alongside it. When you receive covered care, Medicare pays its share first, and your Medigap policy pays some or all of the remaining out-of-pocket costs depending on the plan you choose.
Medigap policies are standardized by federal law. In most states, there are ten standardized plans, each identified by a letter: A, B, C, D, F, G, K, L, M, and N. Every Plan G sold by any insurance company in a given state offers the same core benefits — the only differences are the price, the company's customer service, and any extra perks. This standardization makes shopping straightforward: once you decide which letter plan fits your needs, you simply compare premiums across insurers.
It is important to distinguish Medigap from Medicare Advantage (Part C). Medicare Advantage plans replace Original Medicare with a private plan that includes its own network, copays, and rules. Medigap, by contrast, lets you keep Original Medicare and see any doctor nationwide who accepts Medicare — no networks, no referrals, no prior authorizations for covered services.
Medigap Plans A Through N: What Each Covers
Each standardized Medigap plan covers a different combination of benefits. All plans cover the Part A coinsurance and hospital costs up to an additional 365 days after Medicare benefits are exhausted. Beyond that core benefit, coverage varies.
Plan A: Basic Protection
Plan A is the most basic Medigap policy. It covers Part A coinsurance and hospital costs, Part B coinsurance or copayment, blood (first 3 pints), and Part A hospice care coinsurance. It does not cover the Part A deductible, the Part B deductible, skilled nursing facility coinsurance, or foreign travel emergency care. Plan A premiums are typically the lowest, but the out-of-pocket exposure is the highest.
Plan B: Adds the Part A Deductible
Plan B includes everything in Plan A plus coverage of the Part A hospital deductible. For 2026, the Part A deductible is $1,676 per benefit period. If you are hospitalized, Plan B pays that deductible for you. It still does not cover the Part B deductible, Part B excess charges, or foreign travel emergencies.
Plan C and Plan F: The Comprehensive Plans (Closed to New Enrollees)
Plans C and F are the most comprehensive Medigap options, covering nearly every gap including the Part B deductible. However, as of January 1, 2020, Plans C and F are no longer available to people who became newly eligible for Medicare on or after that date. If you were eligible for Medicare before 2020 and already hold a Plan C or F, you may keep it. If you are newly eligible in 2026, these plans are not an option — Congress closed them to new enrollees to encourage some cost-sharing.
Plan D: Strong Coverage Without Part B Excess Charges
Plan D covers the Part A deductible, skilled nursing facility coinsurance, foreign travel emergency care, and the core benefits. It does not cover the Part B deductible or Part B excess charges — the amounts some doctors charge above the Medicare-approved amount. Plan D is a solid choice if you do not see doctors who charge excess charges and want broad coverage.
Plan G: The Most Popular Choice for New Enrollees in 2026
Plan G has become the most popular Medigap plan for people newly eligible for Medicare since 2020. It covers everything Plan F covers except the Part B deductible. In practical terms, that means Plan G pays the Part A deductible, Part A and Part B coinsurance, skilled nursing facility coinsurance, Part B excess charges, and foreign travel emergency care. You pay the annual Part B deductible yourself — $257 in 2026 — and Plan G covers the rest.
For most new Medicare beneficiaries, Plan G offers the best balance of comprehensive coverage and reasonable premiums. Because the only out-of-pocket cost you face for Medicare-covered services (after the Part B deductible) is essentially zero, budgeting for healthcare becomes predictable.
Plan K and Plan L: Cost-Sharing Plans
Plans K and L are cost-sharing plans with lower premiums but higher out-of-pocket costs. Plan K covers 50% of most cost-sharing items up to an annual out-of-pocket limit of $7,220 in 2026, after which it pays 100%. Plan L covers 75% up to an annual limit of $3,610. These plans suit people who want lower monthly premiums and are comfortable sharing costs up to the annual cap.
Plan M: A Middle-Ground Option
Plan M covers the Part A deductible at 50% and includes the core benefits plus skilled nursing facility coinsurance and foreign travel emergency care. It does not cover the Part B deductible or Part B excess charges. Plan M appeals to beneficiaries who want moderate premiums and are willing to pay half the Part A deductible themselves.
Plan N: Lower Premiums With Copays
Plan N is the second most popular Medigap plan after Plan G. It covers nearly everything Plan G covers, but with two key differences: you pay a copayment of up to $20 for some office visits and up to $50 for emergency room visits that do not result in inpatient admission. In exchange, Plan N premiums are typically 15% to 30% lower than Plan G. Plan N also does not cover Part B excess charges, so if your doctors charge above the Medicare-approved amount, you would pay the excess yourself.
Plan N is an excellent choice for healthy beneficiaries who visit the doctor infrequently and want to save on monthly premiums while still having strong catastrophic protection.
High-Deductible Plan F and Plan G
For beneficiaries who want the lowest possible premiums, high-deductible versions of Plan F and Plan G are available. These plans cover the same benefits as their standard counterparts, but only after you pay a deductible of $2,870 in 2026. The high-deductible options appeal to people who are comfortable paying more out of pocket in exchange for substantially lower monthly premiums.
Medicare Supplement Costs in 2026: What You Will Actually Pay
Medigap premiums vary widely by plan, insurer, age, location, and rating method. In 2026, typical monthly premiums for a 65-year-old in an average-cost state are approximately:
- Plan A: $90 to $150 per month.
- Plan B: $120 to $180 per month.
- Plan D: $140 to $220 per month.
- Plan G: $130 to $260 per month (varies significantly by state and insurer).
- Plan K: $50 to $90 per month.
- Plan L: $80 to $140 per month.
- Plan M: $110 to $180 per month.
- Plan N: $100 to $200 per month.
- High-Deductible Plan G: $40 to $80 per month.
These ranges are approximate. Premiums in high-cost states like New York or Florida can be significantly higher, while states with community rating may have different pricing structures. Your exact premium depends on the insurer, your zip code, and whether you qualify for household or non-smoker discounts.
How Insurers Set Medigap Premiums
Insurance companies use one of three rating methods to price Medigap policies:
- Community-rated (no-age-rated): Everyone pays the same premium regardless of age. Premiums may increase due to inflation or rising healthcare costs, but not because you get older. New York, Connecticut, and Massachusetts use community rating.
- Issue-age-rated: Your premium is based on the age at which you buy the policy. If you buy at 65, your premium is lower than if you buy at 70, and it will not increase due to age — only due to inflation and claims costs.
- Attained-age-rated: Your premium starts low and increases as you age. This is the most common method. A policy that seems cheap at 65 can become expensive by age 80 as attained-age increases compound.
When comparing quotes, ask the insurer which rating method it uses. An attained-age policy with a low initial premium may cost more over a 20-year retirement than a community-rated or issue-age policy with a higher starting premium.
Medicare Open Enrollment and Your Medigap Rights
Timing matters enormously for Medigap. The best time to buy a Medigap policy is during your Medigap Open Enrollment Period, which begins the month you turn 65 and are enrolled in Part B, and lasts for six months. During this period, you have a guaranteed issue right: insurance companies cannot deny you coverage or charge you more based on pre-existing health conditions.
If you miss this six-month window, insurers can use medical underwriting to deny your application or charge higher premiums based on your health history. Some states offer additional open enrollment periods or guaranteed issue rights beyond the federal minimum — check your state insurance department for local rules.
Note that the Medigap Open Enrollment Period is different from the Medicare Annual Enrollment Period (October 15 to December 7), which is when you can change Medicare Advantage or Part D prescription drug plans. Among all Medicare plans, Medigap plans do not have an annual open enrollment period — outside your initial six-month window, switching Medigap plans generally requires medical underwriting in most states.
How to Choose the Right Medigap Plan
Selecting a Medigap plan involves balancing coverage, premiums, and your personal health profile:
- Assess your health and risk tolerance. If you have chronic conditions or expect frequent medical care, a comprehensive plan like Plan G minimizes surprise bills. If you are healthy and rarely see a doctor, Plan N or a high-deductible plan may save money.
- Compare premiums across insurers. Because benefits are standardized, a Plan G from Company A covers exactly the same services as a Plan G from Company B. Get quotes from at least three to five insurers and ask about discounts for household members or electronic payment.
- Consider the rating method. An attained-age policy may be cheapest today but most expensive in a decade. Project costs over 15 to 20 years, not just the first year.
- Check the insurer's financial stability. Look for companies rated A or higher by AM Best. You want an insurer that will be solvent and responsive decades from now.
- Understand what Medigap does not cover. Medigap does not cover long-term care, vision, dental, hearing aids, eyeglasses, or private-duty nursing. You may need separate coverage for those needs.
- Do not confuse Medigap with Part D. Medigap does not include prescription drug coverage. You will need a separate Part D plan for medications, even if you have Medigap.
Common Medigap Mistakes to Avoid
- Waiting too long to enroll. Missing your six-month Medigap Open Enrollment Period means underwriting, higher premiums, or denial. Enroll when first eligible.
- Choosing based on premium alone. The cheapest premium today may come with attained-age increases that make it the most expensive policy over time.
- Assuming Medicare Advantage and Medigap are interchangeable. You cannot have both. If you enroll in Medicare Advantage, you cannot use a Medigap policy, and vice versa.
- Forgetting Part D. Medigap covers cost-sharing for Parts A and B, but not drugs. Enroll in a Part D plan to avoid the late enrollment penalty.
- Not checking state-specific rules. Massachusetts, Minnesota, and Wisconsin have their own standardized Medigap plans that differ from the national letter plans.
The Bottom Line
Medicare Supplement plans provide peace of mind by capping your out-of-pocket costs and letting you see any Medicare-accepting doctor nationwide. For most new Medicare beneficiaries in 2026, Plan G offers the strongest combination of comprehensive coverage and predictable costs, while Plan N is an excellent lower-premium alternative for healthy individuals. The key is to enroll during your six-month Medigap Open Enrollment Period, compare premiums across multiple insurers, and choose a plan that fits both your health needs and your long-term budget.
Start by getting quotes for Plan G and Plan N from at least three insurers, ask about the rating method and available discounts, and review your Part D prescription drug options at the same time. With the right combination, you can enter retirement knowing your healthcare costs are under control.
Disclaimer: This article is for informational purposes only and does not constitute insurance, financial, or legal advice. Medicare Supplement plan availability, premiums, and rules vary by state and change over time. Consult a licensed insurance agent or your State Health Insurance Assistance Program (SHIP) for guidance tailored to your situation.
