How US health insurance works: the basics for immigrants

Unlike most countries, the US has no single universal public health insurance. Coverage comes from three sources: insurance through an employer, the individual marketplace (ACA — HealthCare.gov), and public programs (Medicaid, Medicare, CHIP). Below, the system is explained with facts, based on HealthCare.gov, CMS (Centers for Medicare & Medicaid Services), Medicaid.gov, and KFF (Kaiser Family Foundation). Figures are as of 2026 and can change yearly.

Key cost terms

Premium — the monthly amount paid whether or not you use care. Deductible — what you pay before the plan starts paying (e.g., a $2,000 deductible means you cover the first $2,000). Copay — a fixed charge per service (e.g., $30 a visit). Coinsurance — a percentage of a service's cost (e.g., 20%). Out-of-pocket maximum — the most you pay in a year for in-network covered services; after that the plan pays 100% of covered benefits. In 2026 this maximum is $10,600 for an individual and $21,200 for a family (it was $9,200 and $18,400 in 2025).

Employer-sponsored insurance (the most common)

Most working-age Americans get insurance through their job. Per KFF (analysis of Census data, March 2025), about 60% of the under-65 population — roughly 165 million people — had employer coverage. The employer usually pays most of the premium, with the rest deducted from the employee's pay.

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The ACA Marketplace (HealthCare.gov)

Those without employer coverage can buy it on the individual marketplace — HealthCare.gov (the ACA, the Affordable Care Act). Open enrollment usually runs from November 1 (for 2026 coverage) to January 15; some state marketplaces set different dates. Income-based premium tax credits (subsidies) are available, generally for those between 100% and 400% of the federal poverty level. Plans come in four “metal” tiers: Bronze (plan pays about 60% on average), Silver (about 70%, the basis for subsidies), Gold (about 80%), Platinum (about 90%). All tiers cover the same 10 essential health benefits; the difference is in cost sharing.

Important for immigrants: lawfully present immigrants can buy Marketplace coverage and may qualify for premium tax credits. In addition, lawfully present immigrants with low income who are ineligible for Medicaid because of their immigration status can still use Marketplace subsidies.

Medicaid and Medicare

Medicaid is for low-income people; eligibility is income-based and varies by state (especially in states that expanded Medicaid). An important rule: many lawfully present immigrants (most green-card holders) must wait five years after gaining status before enrolling in full Medicaid; refugees, asylees, those with 40 work quarters, and military members and their families are exempt. During the wait they can use the Marketplace with subsidies. Medicare is for people 65 and older; it also comes after 24 months of Social Security disability benefits (with no wait for end-stage renal disease and ALS).

Emergency care and EMTALA

Under EMTALA (the Emergency Medical Treatment and Labor Act), Medicare-participating hospitals with an emergency department must screen and stabilize anyone with an emergency condition regardless of insurance, ability to pay, or immigration status; treatment cannot be delayed to ask about payment. But EMTALA guarantees stabilization, not free care — the patient can be billed afterward.

Networks: HMO and PPO

In-network providers and hospitals have a contract with your plan and charge negotiated, lower prices; for out-of-network providers you pay more, or the plan may not cover them at all. An HMO plan usually covers only in-network care (except emergencies) and requires a primary care provider (PCP) and referrals to specialists — cheaper but more limited. A PPO plan allows out-of-network care without a referral — flexible but more expensive.