Medigap Plan Types: Comparing Plans A Through N

Medicare Supplement Insurance — sold under the federal standardization framework commonly called Medigap — comes in up to 10 lettered plan types, each defined by a specific combination of benefits that fills gaps left by Original Medicare. Understanding how Plans A through N differ in structure, cost-sharing, and benefit scope is essential for beneficiaries navigating the Medicare Supplement Insurance (Medigap) landscape. This page provides a structured comparison of every standardized plan type, the mechanics that govern their design, and the tradeoffs that make one plan more appropriate than another depending on a beneficiary's utilization patterns and financial exposure.

• Definition and scope
• Core mechanics or structure
• Causal relationships or drivers
• Classification boundaries
• Tradeoffs and tensions
• Common misconceptions
• Checklist or steps (non-advisory)
• Reference table or matrix

Definition and scope

Medigap plan types are federally standardized benefit packages regulated under the Social Security Act and implemented through Centers for Medicare & Medicaid Services (CMS) rulemaking. Federal law — specifically the Omnibus Budget Reconciliation Act of 1990 (OBRA 1990) — required the standardization of Medigap policies so that any Plan G sold in one state delivers the same core benefits as Plan G sold in another state, regardless of which private insurer issues it. Premiums, underwriting practices (outside of guaranteed-issue windows), and customer service vary by insurer, but benefit design does not.

Ten plan types currently exist in the standardized framework: Plans A, B, C, D, F, G, K, L, M, and N. Plans E, H, I, and J were eliminated from new sales after June 1, 2010, under CMS standardization rules, though policies purchased before that date can remain in force. As of January 1, 2020, Plans C and F — which cover the Medicare Part B deductible — are no longer available to beneficiaries who became eligible for Medicare on or after that date, per the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA) (CMS, Medigap Policy Basics).

The scope of standardization covers 9 defined benefit categories: Part A coinsurance and hospital costs, Part B coinsurance or copayment, Part A hospice care coinsurance, skilled nursing facility coinsurance, Part A deductible, Part B deductible, Part B excess charges, foreign travel emergency coverage, and blood (first 3 pints). Each plan type includes or excludes specific items from this list.

Core mechanics or structure

Every standardized Medigap plan builds from a required core: Plan A establishes the minimum benefit floor. All plans must cover Part A hospital coinsurance and up to 365 additional inpatient days after Medicare benefits are exhausted, plus the cost of the first 3 pints of blood and Part B coinsurance or copayments.

Plans B through N add layers to this floor in differing combinations. Plan B adds the Part A deductible. Plan D adds the Part A deductible and skilled nursing facility (SNF) coinsurance but does not cover the Part B deductible or excess charges. Plan G covers everything Plan F covers except the Part B deductible, making it the most comprehensive plan available to new Medicare enrollees after 2020. Plan N covers Part B coinsurance but introduces cost-sharing in the form of copayments up to $20 for office visits and up to $50 for emergency department visits that do not result in inpatient admission.

Plans K and L operate on a cost-sharing model rather than a first-dollar coverage model. Plan K covers 50% of most covered benefits (with the exception of the Part B coinsurance for preventive care, which is covered at 100%) and includes an annual out-of-pocket limit — set at $7,220 for 2024 (CMS, 2024 Medigap Benefit Chart). Plan L uses a 75% coverage ratio and carries an out-of-pocket limit of $3,610 for 2024. Once a beneficiary meets the annual out-of-pocket limit under Plan K or L, the plan pays 100% of covered costs for the remainder of the calendar year.

Foreign travel emergency coverage — available in Plans C, D, F, G, M, and N — pays 80% of medically necessary emergency care outside the United States after a $250 annual deductible, up to a lifetime maximum of $50,000.

Causal relationships or drivers

The variation in plan benefit structures reflects a deliberate policy framework designed to balance premium affordability against coverage comprehensiveness. Plans with higher cost-sharing (K, L, N) carry lower monthly premiums because the beneficiary retains a larger share of routine cost risk. Plans with first-dollar or near-first-dollar coverage (F, G) carry higher premiums because the insurer assumes a larger share of per-claim exposure.

The elimination of Plans C and F for new enrollees starting in 2020 stems directly from MACRA's prohibition on Medigap plans covering the Part B deductible for newly eligible beneficiaries. The legislative rationale, as stated in the MACRA conference report, was that first-dollar coverage of the Part B deductible reduces the price signal that discourages unnecessary utilization of Part B services.

Plan G has become the de facto high-coverage benchmark for beneficiaries eligible after 2020, occupying the position that Plan F held for prior cohorts. The Part B deductible — set at $240 for 2024 (CMS, Medicare Costs) — is the sole item distinguishing Plan G from the now-restricted Plan F.

Part B excess charges, covered only by Plans F and G, arise when a provider does not accept Medicare assignment and bills above the Medicare-approved amount. Federal law caps excess charges at 15% above the Medicare-approved rate (the Medicare limiting charge), but 27 states plus the District of Columbia have "mandatory assignment" laws that eliminate excess charges entirely, making this benefit irrelevant for residents of those states (CMS, Medicare & You 2024).

Classification boundaries

Not all Medigap plans are available in all states. Massachusetts, Minnesota, and Wisconsin standardize their Medigap policies under different state-defined frameworks rather than the federal lettered system — beneficiaries in those states encounter plans with different names and structures.

High-deductible versions of Plans F and G exist as distinct sub-types. The high-deductible Plan G requires the beneficiary to pay an annual deductible of $2,800 (2024) before the plan begins paying benefits (CMS, 2024 Medigap Out-of-Pocket Limits). This sub-type is distinct from standard Plan G and is not offered by all insurers in all states.

Plan M covers 50% of the Part A deductible rather than 100%, positioning it as a partial-deductible plan at a lower premium than Plan G or D. Plan M is among the least-commonly offered plan types; insurer participation varies significantly by state.

Tradeoffs and tensions

The central tension in Medigap plan selection runs between premium cost and out-of-pocket certainty. Plan G eliminates nearly all unpredictable cost-sharing after the Part B deductible is met, but its premium can exceed Plans K or N by $100 or more per month depending on insurer, age, and geography. A beneficiary who uses few Part B services in a given year may pay more in net total cost (premium plus cost-sharing) under Plan G than under Plan N.

Plan N introduces a structural asymmetry: it does not cover Part B excess charges. Beneficiaries in states without mandatory assignment laws who see non-participating providers are exposed to charges up to 15% above the Medicare-approved rate, without any Medigap protection under Plan N. This exposure is invisible at the time of plan selection but can materialize as unexpected billing.

Plans K and L's out-of-pocket limits reset on January 1 each calendar year regardless of when the beneficiary enrolled, creating a proportional risk for beneficiaries who enroll mid-year.

Premium rating methods — community rating (same premium regardless of age), issue-age rating (premium set at age of purchase), and attained-age rating (premium increases as the beneficiary ages) — are not standardized federally and vary by state and insurer. An attained-age-rated Plan G may be cheaper initially than a community-rated Plan G but can become substantially more expensive over a decade of enrollment.

For a broader view of how Medicare costs, premiums, deductibles, and copays interact with supplement plan design, the structural relationship between Original Medicare's cost-sharing schedule and Medigap benefit triggers is foundational.

Common misconceptions

Misconception: Plan F is the "best" Medigap plan.
Plan F was the most comprehensive plan available and historically enrolled the largest share of Medigap beneficiaries, but it is no longer available to those who became eligible for Medicare on or after January 1, 2020. For eligible enrollees, Plan G provides equivalent coverage for all benefits except the Part B deductible.

Misconception: Medigap covers prescription drugs.
Medigap plans do not include prescription drug coverage. Beneficiaries who want drug coverage must enroll in a standalone Medicare Part D prescription drug plan or a Medicare Advantage plan that includes drug coverage. Medigap is compatible only with Original Medicare (Parts A and B).

Misconception: All 10 plan types are available from every insurer.
Insurers are required to offer Plan A and — if they offer any other plans — Plan C or Plan F (for eligible beneficiaries). Beyond those requirements, insurers choose which plan types to sell. Plan M, for example, is offered by a limited subset of carriers nationally.

Misconception: Medigap enrollment is open year-round with guaranteed issue.
The 6-month Medigap Open Enrollment Period begins on the first day of the month in which a beneficiary is both age 65 or older and enrolled in Medicare Part B. Outside of this window and certain guaranteed-issue rights, insurers in most states can use medical underwriting to deny coverage or charge higher premiums based on health status.

Misconception: Medigap plans cover dental, vision, and hearing.
Standard Medigap benefits do not cover dental care, vision correction, hearing aids, or long-term custodial care. These fall outside Original Medicare's benefit scope entirely and are not included in the standardized Medigap benefit categories. Resources outlining what Medicare does not cover address this gap in detail.

Checklist or steps (non-advisory)

Factors to identify when comparing Medigap plan types:

• [ ] Determine Medicare eligibility date — confirms which plan types (C, F) are available or restricted
• [ ] Identify the state of residence — confirm whether the state uses federal standardization or a state-specific framework (Massachusetts, Minnesota, Wisconsin)
• [ ] Confirm whether the state has mandatory assignment laws affecting Part B excess charge exposure
• [ ] Obtain the current Part A deductible, Part B deductible, and SNF coinsurance figures from CMS for the applicable benefit year
• [ ] Note the annual out-of-pocket limits for Plans K and L for the applicable calendar year
• [ ] Identify the premium rating method used by each insurer (community, issue-age, attained-age)
• [ ] Determine whether a high-deductible plan variant (Plan F or G) is available from carriers in the service area
• [ ] Check whether the 6-month Medigap Open Enrollment Period has begun or a guaranteed-issue right applies
• [ ] Compare total estimated annual cost: monthly premium × 12 plus expected cost-sharing under each plan scenario
• [ ] Confirm that any insurer being evaluated is licensed in the applicable state through the state insurance commissioner's registry

The National Medicare Authority home resource consolidates foundational Medicare structure information that provides context for plan comparison decisions.

Reference table or matrix

Medigap Standardized Plan Benefits — Federal Framework (2024)

*Plans C and F not available to beneficiaries with Medicare eligibility on or after January 1, 2020 (MACRA 2015, CMS).
†Plan N pays Part B coinsurance except for copayments up to $20 for office visits and up to $50 for emergency department visits not resulting in inpatient admission.

Source: CMS Medigap Policy Basics and 2024 Benefit Chart.