What Does Medigap Cover? Benefits by Plan Type

Medicare Supplement insurance, also called Medigap, is private coverage you buy on top of Original Medicare to pay the cost-sharing it leaves to you. In my work reviewing plans from hundreds of carriers, I've found most buyers don't realize how large those leftover costs can be until they're already in the hospital. 

The federal government standardizes all 10 plan types. Plan G from Aetna and Plan G from Mutual of Omaha cover the same benefits in every state. Our analysis focuses on the premium side, where identical Plan G coverage can cost $100 or more per month less at one company than another.

Medigap pays the cost-sharing Original Medicare assigns to you. It covers Part A coinsurance, Part B coinsurance, skilled nursing facility costs and in some plans, Part B excess charges and the $1,736 Part A hospital deductible per benefit period in 2026. Medigap pays only after Medicare processes and partially pays a claim first.

No Medigap plan covers prescription drugs. You'll need a separate Medicare Part D plan for drug coverage, an exclusion that has applied since 2006. Dental, vision, hearing aids, private-duty nursing and long-term custodial care are also excluded from all 10 standardized plans. 

Nursing home custodial care runs tens of thousands of dollars per year, and prescription drug costs accumulate annually without a Part D plan.

Medigap premiums range from $61 to $354 per month depending on the plan letter, your age and your state. The average at age 65 is $189 per month, rising to $238 by age 75, an increase of $588 per year from aging alone. 

Identical plan letters can differ by $100 or more per month between insurers in the same state. In our analysis, comparing at least three insurers during your Open Enrollment Period is the single most reliable way to cut your premium without changing your benefits.

Plans C and F aren't available to people who became eligible for Medicare on or after January 1, 2020. High-deductible figures reflect the 2026 deductible of $2,950 as per CMS.

The Medigap Open Enrollment Period begins the first month you're both 65 or older and enrolled in Medicare Part B. It lasts six months and is the only window when insurers cannot deny a Medigap policy or charge more because of a pre-existing condition, regardless of health status. 

After this window closes, insurers in most states can use medical underwriting to decline your application or charge you more. In my experience reviewing enrollment patterns, the most common mistake buyers make is waiting until a health event forces the decision.

Medigap and Medicare Advantage solve the same problem in opposite ways. Medigap works alongside Original Medicare. You see any provider who accepts Medicare and the plan pays your cost-sharing. Medicare Advantage replaces Original Medicare with a private plan that restricts you to a network.   

In many markets in 2026, Medicare Advantage plans averaged a $0 monthly premium, but network restrictions and prior authorization requirements come with it. If you have chronic conditions or see specialists regularly, provider freedom outweighs the premium savings. A healthy buyer on a fixed income often finds the $0 premium more practical.

Medigap is the right choice for enrollees who want predictable costs and the freedom to see any Medicare-accepting provider. For buyers prioritizing a low monthly premium and comfortable with a network, Medicare Advantage is more competitive. If you have a chronic condition and see specialists regularly, provider access matters more than the premium gap.

The right Medigap plan depends on how often you use health care, whether your providers accept Medicare assignment (meaning they bill no more than Medicare's approved rate) and how much premium certainty you need.

Plan G is the most comprehensive option available to new Medicare enrollees. It covers Part B excess charges, skilled nursing costs and the full Part A deductible. Only the $283 annual Part B deductible falls to you.

Plan N costs less monthly but requires copays of up to $20 for office visits and $50 for emergency room visits. Plans K and L suit buyers who want lower monthly costs and can absorb a defined share of each bill. Plan K's out-of-pocket cap is $8,000 in 2026 and Plan L's cap is $4,000.