Medicare vs. Medicaid: Two Programs, Very Different Rules

Who each program covers

Medicare and Medicaid share a name prefix, but they serve different populations and operate under different rules.

Medicare is a federal program administered by the Centers for Medicare and Medicaid Services (CMS). Eligibility is based primarily on age: U.S. citizens and permanent residents who are 65 or older and have at least 10 years of Medicare-covered work history can enroll. Younger people may also qualify if they have received Social Security Disability Insurance (SSDI) for 24 months, or if they have amyotrophic lateral sclerosis (ALS) or end-stage renal disease (ESRD).

Medicaid is a joint federal-state program. The federal government sets baseline requirements, but each state designs and administers its own version, which means income thresholds, covered services, and enrollment processes differ by state. Under the Affordable Care Act, states that expanded Medicaid generally cover adults up to 138 percent of the federal poverty level. Non-expansion states apply narrower rules. Medicaid also covers children through the Children's Health Insurance Program (CHIP) in most states.

For a closer look at how Medicare is structured internally, see how Medicare Parts A, B, C, and D work.

How costs compare

Cost structure is one of the clearest differences between the two programs.

Medicare uses a premium-plus-cost-sharing model. Most people pay no premium for Part A (hospital insurance) if they have sufficient work history, but Part B (medical insurance) carries a standard monthly premium set annually by CMS. Enrollees also face deductibles and coinsurance for most services. People who want to limit out-of-pocket exposure often purchase a Medicare Supplement (Medigap) policy. What to look for in a Medigap plan covers the factors worth reviewing before enrolling.

Medicaid, by contrast, typically charges little or nothing at the point of care. Federal rules cap cost-sharing for most Medicaid enrollees at nominal amounts, and many states charge no premiums at all. This makes Medicaid substantially more affordable on a month-to-month basis for people who qualify.

What each program covers and where the gaps are

Medicare covers inpatient hospital care (Part A), outpatient and physician services (Part B), and prescription drugs (Part D). Medicare Advantage (Part C) bundles these through private insurers and may include some additional benefits. However, Medicare does not generally cover routine dental, vision, or hearing care, and its long-term care coverage is limited to short-term skilled nursing stays following a qualifying hospital admission.

Medicaid covers a broader set of services in many states, including long-term care in nursing facilities and home- and community-based settings. This is a meaningful difference for older adults who need ongoing personal care. Medicaid's long-term care coverage and eligibility rules explains the income and asset considerations in more detail.

People who rely solely on Medicare sometimes face surprise costs in areas they assumed were covered. Common misconceptions about Medicare coverage addresses several of the most frequent misunderstandings.

Dual eligibility: when both programs apply

Some people qualify for Medicare and Medicaid at the same time. CMS refers to them as dual eligible beneficiaries. In this situation, Medicare generally pays first and Medicaid covers some or all of the remaining costs, including premiums, deductibles, and coinsurance. Medicaid may also pay for services Medicare excludes, such as long-term personal care.

Dual eligibility is more common among low-income older adults and people with disabilities who have limited income and assets despite qualifying for Medicare through age or disability status. Enrollment in both programs is not automatic; a person must apply to their state Medicaid agency separately.

Medicare and Medicaid operate alongside other federal benefit programs. If you are also sorting out Social Security income questions, the difference between SSI and Social Security retirement may be useful context.

This article is for general informational purposes only and is not medical, legal, or financial advice. Eligibility rules and covered services change periodically and vary by state. Consult a licensed insurance counselor, your State Health Insurance Assistance Program (SHIP), or a qualified professional for guidance specific to your situation.