Medicare Gaps: What Original Medicare Doesn't Cover (and How to Plug Them)

Navigating Uncovered Expenses in Medicare

Medicare is a remarkable program — it provides essential health coverage to more than 65 million Americans. But "Medicare covers it" is not the same as "Medicare covers everything." Original Medicare (Parts A and B) leaves real gaps, and those gaps can blindside beneficiaries who haven't planned for them.

Here at LifeHelm, we'd rather you see the gaps before they hit your wallet. This is a plain-English guide to what Original Medicare doesn't cover, why the gaps exist, and the main ways you can fill them.

The Real Gaps in Original Medicare

Deductibles, Coinsurance, and the Open-Ended 20%

Original Medicare comes with the typical insurance cost-sharing structure — but with one critical difference we'll cover in the next section.

For 2026:

• Part A inpatient hospital deductible: $1,736 per benefit period

• Part B annual deductible: $283

• Part B coinsurance after deductible: typically 20% of approved costs, with no annual cap

The first two are predictable. The third is the one to worry about — there is no limit on what 20% of Medicare-approved charges can add up to.

No Annual Out-of-Pocket Maximum

This is the largest structural gap in Original Medicare. Most private health insurance plans cap your annual out-of-pocket costs (call it $7,000 or $10,000 depending on the plan). Once you hit that cap, the plan pays 100% for the rest of the year.

Original Medicare has no such cap. A serious illness or extended hospital stay can produce open-ended costs. This is the single biggest reason most Original Medicare enrollees buy supplemental coverage.

Services Original Medicare Doesn't Cover

Medicare was designed for hospital and physician care, not for the full spectrum of health needs. The following are generally not covered:

• Routine dental care — exams, cleanings, fillings, dentures

• Routine vision care — eye exams for prescription glasses, contact lenses

• Hearing aids and routine hearing exams

• Long-term care (also called custodial care) — covered separately below

• Cosmetic surgery

• Most acupuncture (some coverage for chronic low back pain)

• Routine foot care

• Most overseas medical care

Many of these add up faster than people expect. Hearing aids alone can run $2,000 to $6,000 per pair without insurance.

Prescription Drugs (Where Part D Comes In)

Original Medicare doesn't cover most prescription drugs you'd pick up at a pharmacy. (Drugs administered in a hospital or doctor's office may be covered under Part B.)

For prescription coverage, you'd add a separate Medicare Part D plan or choose a Medicare Advantage plan that bundles Part D coverage. Either way, the new $2,100 annual out-of-pocket cap on Part D drugs (in 2026) limits your exposure for prescription costs — a major improvement over the previous design.

The Big One: Long-Term Care

Long-term care — assistance with daily activities like bathing, dressing, eating, and getting around — is the largest uncovered expense most retirees face. Medicare does not pay for ongoing custodial care, whether at home, in assisted living, or in a nursing facility.

What Medicare does cover, briefly:

• Short-term skilled nursing facility care — up to 100 days following a qualifying hospital stay, with daily coinsurance after day 20 ($217/day in 2026 for days 21–100)

• Home health care when medically necessary and ordered by a doctor

• Hospice care for terminal illness

But the kind of ongoing care most aging adults eventually need — months or years of help with daily living — is not covered by Medicare. The options to pay for it are:

• Pay out of pocket (median U.S. nursing home cost runs over $100,000/year)

• Long-term care insurance (purchased separately, ideally before age 65)

• Medicaid — if you qualify (which generally requires spending down assets to state-set limits)

• VA benefits if you're a qualifying veteran

This is a planning issue more than an insurance issue. We've written separately about Medicaid eligibility and how it interacts with long-term care.

How to Fill the Gaps

Most Medicare beneficiaries don't rely on Original Medicare alone. The two main ways to fill the gaps:

Medigap (Medicare Supplement Insurance)

Medigap policies are sold by private insurers and are designed to pay some or all of what Original Medicare doesn't — the Part A deductible, Part B coinsurance, hospital coinsurance after day 60, and more. You keep Original Medicare and Medigap pays in addition.

Important features:

• Standardized plans. Medigap plans are labeled with letters (A, B, D, G, K, L, M, N). The benefits at each letter are identical across insurers; only the premium varies. Massachusetts, Minnesota, and Wisconsin have their own standardized plan structures.

• No prescription drug coverage. Medigap policies do not cover Rx. You'd still want a separate Part D plan.

• Most popular for new enrollees: Plan G. Pays nearly everything Original Medicare doesn't, except the annual Part B deductible ($283 in 2026). Plan N is the second-most-popular, with slightly higher cost-sharing in exchange for lower premiums.

• Plan F is no longer available to anyone new to Medicare on or after January 1, 2020. If you had it before that date, you can keep it.

• High-deductible options. High-Deductible Plan G has a 2026 deductible of $2,950 — you pay Medicare cost-sharing up to that amount, then the policy pays 100% — in exchange for substantially lower monthly premiums.

Medicare Advantage as an Alternative

Medicare Advantage plans (Part C) bundle Parts A, B, and usually D into one plan from a private insurer. They also include an annual out-of-pocket maximum for Part A and Part B services — the structural protection Original Medicare lacks.

The trade-off: most Medicare Advantage plans use provider networks, may require referrals for specialists, and limit your provider choice in exchange for lower premiums and bundled extras (vision, hearing, dental, gym memberships). Whether this is a better fit than Original Medicare + Medigap is personal — see our separate guide to Demystifying Medicare for the comparison.

You cannot have both Medigap and Medicare Advantage. It's one or the other.

Other Coverage You Might Have

• Employer or retiree health plan — some employers continue retiree health coverage that pays alongside Medicare. Check the rules before you enroll in Medicare.

• VA benefits — for qualifying veterans; coordinate carefully with Medicare.

• Medicaid — if you qualify based on income, Medicaid acts as secondary coverage and can pay much of what Medicare doesn't.

The Medigap Open Enrollment Window — Don't Miss It

This is the most important deadline most people have never heard of.

Your Medigap Open Enrollment Period is the six-month window that starts the month you turn 65 AND are enrolled in Medicare Part B. During this window, insurance companies can't deny you a Medigap policy, can't charge you more for health conditions, and can't make you wait for coverage on pre-existing conditions.

Outside this window, those guarantees disappear in most states. An insurer can ask about your health, charge you more, deny you outright, or make you wait — which is why some people who switch from Medicare Advantage back to Original Medicare later in life find Medigap unaffordable or unavailable.

A few states (Connecticut, Massachusetts, Maine, New York) have year-round guaranteed-issue rules; most don't. Know your state's rules before you assume you can change your mind later.

The Bottom Line

Original Medicare's gaps come down to four real costs:

• The open-ended 20% Part B coinsurance with no annual cap

• Routine dental, vision, hearing, and long-term care

• Prescription drugs without Part D

• Out-of-network care abroad

Most people address the first three by combining Original Medicare with a Medigap policy and a Part D plan, OR by choosing a Medicare Advantage plan with bundled coverage. The fourth — long-term care — is its own planning problem that no Medicare-related product fully solves.

Whichever path you take, the most consequential decision is your first one, at age 65, during your Medigap Open Enrollment window. Here's to bridging the gaps before they become emergencies.

Sources

• Medicare.gov, "Compare Medigap Plan Benefits." medicare.gov/health-drug-plans/medigap/basics/compare-plan-benefits

• Centers for Medicare & Medicaid Services, "2026 Medicare Parts A & B Premiums and Deductibles" fact sheet (November 14, 2025)

• Centers for Medicare & Medicaid Services, "CY 2026 Medigap High-Deductible Options F, J, G" (October 2025)

• Medicare.gov general program information