Adult expansion Medicaid is a provision of the Affordable Care Act that extends Medicaid coverage to adults under 65 who earn up to 138% of the federal poverty level, roughly $22,000 a year for an individual. Before this change, most states only covered specific groups like pregnant women, people with disabilities, and very low-income parents. Expansion opened the door for millions of adults, particularly those without dependent children, who previously had no path to Medicaid regardless of how little they earned.
How Expansion Changed Medicaid Eligibility
Traditional Medicaid was never designed to cover all low-income people. It used what’s called “categorical eligibility,” meaning you had to fit into a specific group: you needed to be pregnant, have a qualifying disability, be a parent or caretaker of a dependent child, or be elderly. A single adult working a low-wage job with no children simply didn’t qualify in most states, even with an income near zero.
The ACA removed those categorical requirements for adults under 65. The law set the income threshold at 133% of the federal poverty level, then added a standard 5-percentage-point income disregard, bringing the effective limit to 138% FPL. For 2025, that translates to about $20,783 for a single person or roughly $37,650 for a family of three. If your household income falls below that line, you qualify based on income alone.
The Coverage Gap in Non-Expansion States
Forty-one states (including Washington, D.C.) have adopted Medicaid expansion. Ten states have not. In those holdout states, a significant problem persists: many adults earn too much to qualify for their state’s traditional Medicaid program but too little to qualify for subsidized insurance through the ACA marketplace. Marketplace subsidies only kick in at 100% of the federal poverty level, and traditional Medicaid in non-expansion states often cuts off well below that. The people stuck in between have no affordable coverage option at all. This is known as the coverage gap, and it disproportionately affects adults without children in low-wage jobs.
What Expansion Medicaid Covers
Expansion Medicaid covers a broad set of services. States must provide what the ACA defines as essential health benefits, which span ten categories: outpatient care, emergency services, hospitalization, maternity and newborn care, mental health and substance use treatment, prescription drugs, rehabilitative services and devices, lab work, preventive care and chronic disease management, and pediatric services. In practice, most enrollees pay little to nothing out of pocket. There are no premiums in most states, and copays, if any, are minimal.
Mental health and substance use treatment coverage is particularly significant for the expansion population. Many adults who gained coverage through expansion had gone years without access to behavioral health services, and the requirement that these be covered on par with physical health conditions has made a measurable difference in treatment access.
How It’s Funded
One reason expansion has been politically contentious is cost, so the federal government sweetened the deal considerably. For the first three years (2014 through 2016), the federal government paid 100% of the cost of covering newly eligible adults. That rate gradually stepped down: 95% in 2017, 94% in 2018, 93% in 2019, and 90% from 2020 onward. That 90% federal match is permanent under current law and far more generous than the standard Medicaid matching rate, which varies by state but averages around 60%. States that expand are responsible for only 10 cents of every dollar spent on the expansion population.
Health Outcomes in Expansion States
The effects of expansion on preventive care have been well documented. In expansion states, use of cancer screenings (colon, breast, and cervical), influenza vaccination, and HIV testing has been consistently higher than in non-expansion states. Among lower-income populations specifically, colon cancer screening and HIV testing saw statistically significant increases after expansion took effect, and those gains held steady from 2014 through 2019. Reducing financial barriers to routine screenings means catching diseases earlier, when treatment is more effective and less expensive.
Rural communities have felt the impact acutely. According to the American Hospital Association, 74% of rural hospital closures have occurred in states where Medicaid expansion was either not in place or had been implemented for less than a year. Expansion brings paying patients into hospitals that would otherwise absorb the cost of uncompensated care, helping keep facilities open in areas where the nearest alternative may be an hour’s drive away.
How to Apply
If you live in an expansion state and think you might qualify, you can apply in several ways. The most common route is through your state’s Medicaid agency website or through HealthCare.gov, which will screen your income and automatically determine whether you qualify for Medicaid or for marketplace coverage with subsidies. You can also apply by phone, through a certified enrollment partner, or by mailing in a paper application (expect results within about two weeks with the mail option). Unlike marketplace insurance, Medicaid doesn’t have a limited enrollment window. You can apply any time of year.
If you’re in one of the ten states that haven’t expanded, applying for traditional Medicaid is still worth trying if you fall into one of the categorical eligibility groups. But if you’re a childless adult above your state’s Medicaid income limit and below 100% FPL, you’re likely in the coverage gap with no subsidized option currently available.