Medicare Supplement Plans: Coverage Gaps Explained

Medicare is a vital health insurance program for individuals aged 65 and older, as well as for some younger people with disabilities. While it provides broad coverage, it doesn’t pay for everything. This is where Medicare Supplement Plans, also known as Medigap, come into play. These private insurance plans are designed to fill in the “gaps” that Original Medicare (Part A and Part B) does not cover.
Original Medicare covers hospital care (Part A) and medical services (Part B), but it leaves beneficiaries responsible for out-of-pocket expenses like deductibles, coinsurance, and copayments. For example, in 2025, the Part A deductible is over $1,600 per benefit period, and Part B typically only covers 80% of approved medical services, leaving the remaining 20% for the patient to pay.
Medigap plans help cover these out-of-pocket costs. There are several standardized plans available (labeled A through N), and while coverage varies slightly between them, all aim to reduce financial uncertainty for beneficiaries. Plan G, for instance, is among the most popular Medigap plans because it covers nearly all of the out-of-pocket expenses except the Part B deductible.
Despite their benefits, Medigap plans do not cover everything. One major coverage gap is prescription drugs. Medigap policies sold after 2006 do not include drug coverage, so beneficiaries must enroll in a separate Medicare Part D plan for this. Another common misconception is that Medigap plans cover long-term care, such as stays in nursing homes. In reality, neither Original Medicare nor Medigap includes long-term custodial care, which must be paid out-of-pocket or through separate insurance.
Additionally, Medigap doesn’t cover routine dental, vision, or hearing care. Services like eye exams for glasses, hearing aids, and dental cleanings are typically excluded unless beneficiaries enroll in additional standalone plans or Medicare Advantage plans that offer these benefits.
Travel coverage is another area where Medigap can help, but with limitations. Some plans, such as Plan G and Plan N, provide emergency health coverage when traveling outside the U.S., but only up to certain limits and with specific conditions. This is useful for retirees who plan to travel internationally, but it’s important to understand the restrictions.
In summary, while Medigap plans provide essential protection against high out-of-pocket costs not covered by Original Medicare, they do not offer complete coverage. Beneficiaries should be aware of what is and isn’t covered, including the need for separate plans for prescription drugs and long-term care. Understanding these gaps is key to building a comprehensive healthcare strategy in retirement.