Medicaid expansion and the coverage gap
Before 2014, Medicaid was mostly closed to adults who did not fit a traditional category. You could be a parent, a pregnant woman, an older adult, or a person with a disability and qualify at a low income. But a working adult without dependent children, however little they earned, generally could not get Medicaid at all, no matter how poor they were. The Affordable Care Act changed that, and the change is called Medicaid expansion.
What expansion did
Expansion created a new eligibility group: adults under 65 whose household income is at or below 133 percent of the federal poverty level, with a 5 percentage point income disregard that makes the effective limit 138 percent. No category is required. You do not need to have children, be pregnant, or have a disability. You need to be under 65, not enrolled in Medicare, and below the income line in a state that adopted expansion. The federal government pays 90 percent of the cost of care for this group, and the state pays 10 percent.
The Supreme Court's 2012 decision in National Federation of Independent Business v. Sebelius made expansion optional for states rather than mandatory. That single decision is why Medicaid looks so different across state lines today. Most states plus the District of Columbia have adopted expansion; a minority have not. The list has changed over the years as states have adopted it, so this site does not print a fixed list that could go stale: check whether your state is an expansion state before you assume anything about your own eligibility.
The coverage gap
In a state that did not expand, an adult without dependent children generally cannot get Medicaid at any income, unless they qualify through age or disability. Parents in those states can qualify, but often only at very low income limits set by the state. That leaves a group of people in what is called the coverage gap: they earn too little to qualify for marketplace premium tax credits, which generally begin at 100 percent of the federal poverty level, but they do not fit any traditional Medicaid category either.
Being in the coverage gap does not mean being without any option, but the options are thinner. Emergency Medicaid can pay for emergency treatment for a life-threatening condition even for people who do not otherwise qualify. Some states run state-funded programs that cover some of the gap population. Community health centers charge on a sliding scale based on income, and hospitals have charity-care programs. None of these is the same as full Medicaid coverage, and none should be described as if it were.
Expansion vs. non-expansion, side by side
| Situation | Expansion state | Non-expansion state |
|---|---|---|
| Childless adult, income below 138% FPL | Generally qualifies for Medicaid | Generally does not qualify, unless aged or disabled |
| Parent, very low income | Qualifies (expansion covers parents too) | May qualify, at a state-set limit that can be far below 138% |
| Adult between 100% and 138% FPL | Medicaid | Marketplace coverage with premium tax credits, if otherwise eligible |
| Adult below 100% FPL, no category | Medicaid | The coverage gap: generally neither Medicaid nor subsidized marketplace coverage |
What if you move between states?
Medicaid does not travel with you. Eligibility is decided by the state where you live, and moving to a new state means applying there under that state's rules. An expansion adult who moves to a non-expansion state can lose coverage entirely, and a person in the coverage gap who moves to an expansion state can gain it. If a move is planned, apply in the new state as soon as you arrive, and do not assume a grace period that your new state has not promised. Coverage in the old state generally ends when you are no longer a resident there.
The gap in one sentence
The coverage gap is the space between a non-expansion state's low parent limits and the marketplace's 100 percent floor, and it exists only because expansion is a state choice.
A note on changing rules. Federal rules for expansion adults are changing, with new federal requirements scheduled to phase in from 2027. Because the details and the timing are set state by state, this guide does not state them as current rules: if you are applying as an expansion adult, confirm the current requirements with your state Medicaid agency before you rely on anything on this page.
Sources: 42 U.S.C. section 1396a(a)(10)(A)(i)(VIII); 42 C.F.R. section 435.603; HealthCare.gov, Medicaid expansion; Medicaid.gov, Medicaid expansion resources; National Federation of Independent Business v. Sebelius (2012).