Question
Is health insurance mandatory in the US?
Short answer
Not under federal law: there has been no federal penalty since 2019. But a few states require it, and some visas do too.
States that require coverage
California, Massachusetts, New Jersey, Rhode Island and Washington, D.C. charge a tax penalty if you go without coverage, unless you qualify for an exemption. Vermont requires coverage but has no penalty. Rules can change, so check your state's tax agency or insurance marketplace.
Visas with their own rules
Some visas set minimum coverage, notably J-1 exchange visitors and their dependents. Universities often require international students to carry the school plan or an equivalent.
Why go insured even where it's optional
US medical care is expensive: a hospital stay can cost tens of thousands of dollars. A plan's out-of-pocket maximum caps what you pay in a year for covered care.
This is general information about how US policies usually work. Your own policy's wording and your state's rules decide the details.