Insurance against loss by illness or bodily injury. Health insurance provides coverage for medicine, visits to the doctor or emergency room, hospital stays and other medical expenses. Policies differ in what they cover, the size of the deductible and/or co-payment, limits of coverage and the options for treatment available to the policyholder. Health insurance can be directly purchased by an individual, or it may be provided through an employer. Medicare and Medicaid are programs which provide health insurance to elderly, disabled, or un-insured individuals.

Prior to the ACA as of 2007, about 9% of Americans were covered under health insurance purchased directly,[53] with average out-of-pocket spending is higher in the individual market, with higher deductibles, co-payments and other cost-sharing provisions.[72][89][90] While self-employed individuals receive a tax deduction for their health insurance and can buy health insurance with additional tax benefits, most consumers in the individual market do not receive any tax benefit.[91]

Generally, group health insurance plans cover the cost of medical office visits for illness and checkups, hospitalization, emergency room services, ambulance transportation, operations, physical therapy, and even prescription drugs, to provide several examples of potentially covered health care services. But, every plan is different and it behooves an employee to become familiar with the details of his or her employer's plan before the benefit is needed.
Premiums, or the cost of the medical coverage, are based on some factors including country of origin, age, medical history, etc. It is advised to have more comprehensive insurance for US medical coverage because it can cost a lot, but the costs of not having it can be much higher. For example, the tests and scans doctors often run are costly and typically not covered by budget medical insurance plans.
Health insurance in the United States is any program that helps pay for medical expenses, whether through privately purchased insurance, social insurance, or a social welfare program funded by the government.[1] Synonyms for this usage include "health coverage", "health care coverage", and "health benefits". In a more technical sense, the term "health insurance" is used to describe any form of insurance providing protection against the costs of medical services. This usage includes private insurance and social insurance programs such as Medicare, which pools resources and spreads the financial risk associated with major medical expenses across the entire population to protect everyone, as well as social welfare programs like Medicaid and the Children's Health Insurance Program, which both provide assistance to people who cannot afford health coverage.