Uninsured and Underinsured Americans: Challenges and Resources

Roughly 25.6 million Americans lacked health insurance in 2022, according to the U.S. Census Bureau's Current Population Survey — and that number tells only part of the story. A separate, quieter problem sits just beneath it: tens of millions more hold coverage that collapses the moment they actually need it. This page examines both populations, how they end up where they are, what the practical consequences look like, and where meaningful help actually exists.

Definition and scope

The uninsured are straightforward to define: no active health insurance coverage, public or private. The underinsured are trickier, and that's where the more interesting tension lives.

The Commonwealth Fund, which publishes the Biennial Health Insurance Survey, defines adults as underinsured when their out-of-pocket costs (excluding premiums) exceed 10 percent of income — or 5 percent for those below 200 percent of the federal poverty level — or when their deductible alone reaches 5 percent of income. By that measure, the Commonwealth Fund's 2023 survey found that 43 percent of working-age adults were either uninsured or underinsured at some point during the prior year.

That 43 percent figure deserves a moment. It means the insured/uninsured binary, while useful, misses a substantial share of the population living one diagnosis away from financial disruption.

The Kaiser Family Foundation tracks this population across demographic lines. Uninsured rates are highest among adults aged 19–34, Hispanic adults (at roughly 19 percent), and adults in states that did not expand Medicaid under the Affordable Care Act. Texas, Florida, and Georgia consistently appear among states with the largest uninsured populations in raw numbers.

How it works

Coverage gaps form through several distinct mechanisms, not a single failure.

The Medicaid gap affects adults in non-expansion states who earn too much to qualify for Medicaid under pre-ACA rules but too little to receive marketplace subsidies, which begin at 100 percent of the federal poverty level. As of 2024, 10 states had not adopted Medicaid expansion (KFF State Health Facts), leaving an estimated 1.5 to 4 million adults in this gap depending on the methodology used.

Job-based coverage loss triggers uninsured spells during unemployment, job transitions, or shifts to part-time or gig-economy work. Employer-sponsored insurance covers roughly 54 percent of the U.S. population (KFF Employer Health Benefits Survey 2023), making job continuity effectively a proxy for coverage continuity for more than half the country.

Underinsurance mechanics often operate through high-deductible health plans (HDHPs). The IRS defines an HDHP as any plan with a deductible of at least $1,600 for individual coverage in 2024 (IRS Revenue Procedure 2023-23). Enrollment in HDHPs grew from 4 percent of covered workers in 2006 to 29 percent by 2022 (KFF Employer Health Benefits Survey), and while pairing them with Health Savings Accounts offers tax advantages, lower-income workers often cannot fund an HSA at a level that meaningfully offsets the deductible exposure.

Common scenarios

The population described above isn't abstract. Four common situations account for the bulk of coverage gaps:

  1. Gig and part-time workers who are ineligible for employer coverage and whose income fluctuates too much for stable marketplace enrollment.
  2. Young adults aged 19–26 who age off a parent's plan and enter the labor market without employer benefits — the leading entry point into uninsured status.
  3. Low-income adults in non-expansion states caught in the Medicaid coverage gap described above.
  4. People with employer coverage but high deductibles who delay care or forgo prescriptions because the out-of-pocket costs are prohibitive before the deductible clears.

The fourth scenario is where underinsurance becomes clinically significant. Research published in Health Affairs has documented that cost-related care avoidance is nearly as common among underinsured adults as among the fully uninsured — a finding that reframes healthcare access and equity as a continuum rather than a switch.

Decision boundaries

Distinguishing which category applies — and therefore which resources are relevant — depends on a few key thresholds.

Uninsured vs. underinsured: If there is no active coverage, the relevant entry points are Medicaid eligibility screening, ACA marketplace special enrollment periods, CHIP for children and some pregnant adults, and community health centers that operate on sliding-scale fees under the Health Resources and Services Administration's 330 grant program (HRSA Health Center Program).

Medicaid-eligible vs. marketplace-eligible: Income determines the fork. At or below 138 percent of the federal poverty level in expansion states, Medicaid applies. From 100 to 400 percent of FPL, premium tax credits are available on the marketplace. The Affordable Care Act overview covers subsidy structure in detail.

Underinsured with an HSA-eligible plan vs. without: Adults in HDHPs who are HSA-eligible can contribute up to $4,150 (individual) or $8,300 (family) in 2024 (IRS Publication 969) to offset deductible exposure pre-tax. Those in non-HSA-qualifying plans have fewer structural buffers, making them more dependent on hospital financial assistance programs and healthcare costs and billing navigation.

The broader U.S. coverage landscape — how healthcare coverage options interact, overlap, and leave gaps — is part of the larger infrastructure described across the National Healthcare Authority.

References