With 10 standardized plan letters, three different pricing methods, and dozens of insurers competing in each state, knowing how to compare Medicare Supplement plans effectively can save you hundreds or even thousands of dollars a year. Nearly 14.5 million Americans carry Medigap policies according to NAIC data, and enrollment continues to grow as more baby boomers reach age 65. This guide walks through every plan letter, highlights the cost differences, and helps you identify the best fit for your situation.
Overview of All Medigap Plan Letters
Federal law standardizes Medigap into 10 plan letters: A, B, C, D, F, G, K, L, M, and N. Each letter covers a specific combination of Medicare cost-sharing gaps. Plans C and F are only available to beneficiaries who became eligible for Medicare before January 1, 2020, because those plans cover the Part B deductible, which MACRA legislation prohibited for newer enrollees.
When you compare Medicare Supplement plans, remember that a Plan G from Mutual of Omaha covers exactly the same benefits as a Plan G from Cigna or AARP/UnitedHealthcare. The only variables between insurers are premium price, customer service quality, and financial stability. This standardization is what makes comparison shopping straightforward once you understand the plan letters.
What Each Plan Covers
Plans A and B: Basic Coverage
Plan A is the most basic Medigap option. It covers Part A coinsurance and hospital costs for an additional 365 days after Medicare benefits are exhausted, the first three pints of blood, Part B coinsurance or copayment, and Part A hospice care coinsurance. Plan B adds coverage for the Part A deductible ($1,632 in 2025). Neither plan covers the Part B deductible, Part B excess charges, skilled nursing facility coinsurance, or foreign travel emergencies.
Plans C and F: Legacy Comprehensive Plans
Plans C and F are the most comprehensive options, covering all Medicare cost-sharing gaps including the Part B deductible. Plan F adds Part B excess charge coverage that Plan C lacks. Because these plans are closed to new Medicare beneficiaries since 2020, their risk pools are aging, which tends to drive premiums higher over time. Monthly premiums for Plan F typically range from $160 to $330 for a 65-year-old. Learn more in our Medicare Plan F guide.
Plan G: The New Standard
Plan G has effectively replaced Plan F as the go-to comprehensive Medigap plan. It covers everything Plan F covers except the Part B deductible. Premiums range from $120 to $280 monthly, and the annual Part B deductible of $257 is the only out-of-pocket cost for covered services. For most beneficiaries, Plan G offers better long-term value than Plan F because the premium savings outpace the deductible cost. See our full Medicare Supplement Plan G analysis and our Plan F vs Plan G comparison.
Plan D: Solid Mid-Tier Option
Plan D covers the same benefits as Plan G minus Part B excess charges. Premiums are slightly lower than Plan G, typically $110 to $240 per month. Plan D is a reasonable choice if your providers all accept Medicare assignment, eliminating the excess charge concern.
Plan N: Popular Budget-Friendly Choice
Plan N covers most of the same benefits as Plan G but requires copays of up to $20 for office visits and up to $50 for ER visits not resulting in admission. It does not cover Part B excess charges. Premiums typically range from $90 to $210 monthly, making it significantly cheaper than Plan G. Explore the tradeoffs in our Medicare Plan N vs Plan G comparison.
Plans K and L: Cost-Sharing Alternatives
Plans K and L take a different approach by covering only a percentage of benefits. Plan K covers 50 percent of most benefits with an annual out-of-pocket limit of $7,060 in 2025. Plan L covers 75 percent with a $3,530 annual limit. Premiums are the lowest of any Medigap plans, often $40 to $120 for Plan K and $60 to $170 for Plan L. These plans suit healthy beneficiaries who want catastrophic protection at the lowest possible premium.
Plan M: The Overlooked Option
Plan M covers 50 percent of the Part A deductible and everything else that Plan D covers. It is not widely sold, and availability varies by state. Premiums are moderately lower than Plan D but not low enough to attract large enrollment numbers.
Cost Comparison Across Plan Letters
To effectively compare Medicare Supplement plans, you need to look beyond the monthly premium and consider total annual cost including deductibles, copays, and potential excess charges. Here are approximate total annual costs for a 65-year-old with moderate healthcare usage, based on 2025 rate filings.
Plan G: $1,700 to $3,617 in total annual cost (premiums plus $257 Part B deductible). Plan N: $1,337 to $2,777 in total annual cost (premiums plus $257 Part B deductible plus estimated $100 to $200 in copays). Plan F: $2,177 to $4,217 in total annual cost (premiums only, no additional out-of-pocket). Plan K: $737 to $1,697 in premiums plus up to $7,060 in cost-sharing if you hit the annual limit.
For a comprehensive cost breakdown, visit our Medigap Cost Comparison Chart.
Three Pricing Methods Insurers Use
How an insurer prices your premium matters as much as which plan you choose. There are three rating methods allowed under federal rules.
Community-rated (also called no-age-rated): Everyone pays the same base premium regardless of age. Starting premiums tend to be higher, but they increase only with inflation and medical cost trends, not with your age. This is the most consumer-friendly method for long-term cost stability.
Issue-age-rated: Your premium is based on your age when you first buy the policy. Younger buyers lock in lower rates. Premiums still increase with inflation and medical trends but not because you get older.
Attained-age-rated: Your premium increases as you age, in addition to inflation and medical trend adjustments. Starting premiums are the lowest of the three methods, but costs can rise substantially over a 20- to 30-year retirement. Most Medigap insurers use attained-age rating.
How to Shop and Compare Quotes
Start at Medicare.gov’s Medigap plan finder, where you can enter your ZIP code and see every plan and insurer available in your area along with their current premiums. You can also call your State Health Insurance Assistance Program (SHIP) for free, unbiased counseling. Independent insurance brokers who represent multiple carriers can pull side-by-side quotes and explain the fine print at no cost to you.
When comparing quotes, match the same plan letter across carriers. Check each insurer’s AM Best financial strength rating (A- or higher is recommended) and their NAIC complaint index. Look for available discounts including nonsmoker, household, annual payment, and electronic funds transfer discounts, which can reduce premiums by 5 to 15 percent.
Frequently Asked Questions
Which Medigap plan is the most popular?
Plan G is currently the most popular Medigap plan among new enrollees, according to NAIC market share data. Plan F retains the largest total enrollment, but its pool is closed to new beneficiaries and shrinking. Plan N is the second most popular choice for new enrollees. For help deciding, see our guide on what is the best Medicare Supplement plan.
Can I switch Medigap plans after I enroll?
You can apply to switch at any time, but outside your initial Medigap Open Enrollment Period, insurers can require medical underwriting in most states. Some states offer annual guaranteed-issue windows. Check your state’s rules before assuming you can switch freely.
Do Medigap plans cover dental, vision, or hearing?
No. Medigap plans only cover gaps in Original Medicare coverage. Dental, vision, and hearing benefits require separate insurance policies or discount plans. Medicare Advantage plans sometimes include these benefits, which is one reason some beneficiaries choose Advantage over Medigap. Compare the two approaches in our Medigap vs Medicare Advantage guide.
Do I need a Part D plan with Medigap?
Yes. Medigap does not cover prescription drugs. You should enroll in a standalone Part D plan during your Initial Enrollment Period to avoid late enrollment penalties. Learn about drug coverage costs in our Part D donut hole article.
Choosing Your Plan
The right plan depends on your health status, visit frequency, provider choices, and budget. If you want comprehensive coverage with minimal hassle, Plan G is the default recommendation. If you are cost-conscious and healthy, Plan N delivers strong coverage at a lower premium. If you want the absolute lowest premium and are comfortable with significant cost-sharing, Plans K or L provide catastrophic protection at bargain rates. Whatever plan you choose, enroll during your Medigap Open Enrollment Period for guaranteed acceptance and the best available rate. For broader context on healthcare coverage decisions, explore our healthcare policy guide and healthcare costs guide.