Public health insurance is coverage funded by the government, primarily through taxes and payroll deductions, rather than by a private company. In the United States, the major public health insurance programs are Medicare, Medicaid, the Children’s Health Insurance Program (CHIP), and VA health care. Together, these programs cover tens of millions of Americans who qualify based on age, income, disability status, or military service.
How Public Insurance Differs From Private Insurance
Private health insurance is typically purchased through an employer or on your own from a for-profit (or nonprofit) insurance company. You or your employer pay monthly premiums, and the insurer covers a portion of your medical costs. Public health insurance works differently: the government collects funding through payroll taxes, general tax revenue, and in some cases modest premiums from enrollees, then uses that money to pay for healthcare services on behalf of people who qualify.
The cost difference can be significant. In 2024, average premiums for individual private insurance ran about $540 to $587 per month depending on whether coverage came through the marketplace or an employer. Public programs like Medicaid, by contrast, charge little or nothing in premiums to most enrollees. Medicare charges premiums for some parts of coverage but is still heavily subsidized by payroll taxes and federal revenue.
Medicare: Coverage for Older Adults and People With Disabilities
Medicare is the federal program most people associate with public health insurance. You’re generally eligible once you turn 65. You can also qualify earlier if you have a permanent disability, end-stage kidney failure requiring dialysis or a transplant, or ALS (Lou Gehrig’s disease). The program is administered by the Centers for Medicare and Medicaid Services.
Medicare is split into parts. Part A covers hospital stays, and it’s financed by a 1.45% payroll tax split equally between you and your employer, so most people don’t pay a separate premium for it. Part B covers doctors’ visits, lab tests, and preventive services. It’s funded by a combination of enrollee premiums, deductibles, and general federal revenue. You can also opt into Part C (Medicare Advantage), which bundles Parts A and B through a private insurer, and Part D, which covers prescription drugs.
Medicaid: Coverage Based on Income
Medicaid is the joint federal-state program that provides health coverage to people with low incomes. Unlike Medicare, which is run entirely at the federal level, Medicaid splits both funding and administration between the federal government and each state. That means eligibility rules, covered services, and the enrollment experience vary depending on where you live.
The federal government’s share of each state’s Medicaid costs is calculated using a formula that compares the state’s average income to the national average. Poorer states receive a larger federal share. States can also receive additional federal matching funds if they choose to cover more people or offer extra services beyond the required minimum.
In most states that expanded Medicaid under the Affordable Care Act, adults qualify if their household income falls below 138% of the federal poverty level. For a single person in 2024, that’s roughly $20,783 per year. For a family of four, it’s about $43,056. States that haven’t expanded Medicaid often have much stricter income limits, sometimes covering only parents or caretakers earning far less than the poverty line.
One important distinction: you can apply for Medicaid at any time of year. There is no limited enrollment window.
CHIP: Health Insurance for Children
The Children’s Health Insurance Program covers kids in families that earn too much to qualify for Medicaid but can’t afford private insurance. States have flexibility in how they run CHIP. Some operate it as a standalone program, some fold it into their existing Medicaid system, and some do a combination of both. Income limits for CHIP typically reach up to 200% of the federal poverty level or higher, depending on the state, which for a family of four in 2024 would be around $62,400 or more.
Like Medicaid, CHIP enrollment is open year-round. If your child qualifies, you don’t need to wait for an annual enrollment period.
VA Health Care: Coverage for Veterans
Veterans who served in the U.S. military may qualify for health care through the Department of Veterans Affairs. Once enrolled, you’re assigned to one of eight priority groups based on your service history, disability rating, income, and whether you qualify for other programs like Medicaid.
Veterans with service-connected disabilities rated at 50% or higher receive the highest priority, along with Medal of Honor recipients. Those with lower disability ratings fall into groups 2 and 3, which also includes former prisoners of war and Purple Heart recipients. Veterans without service-connected disabilities and with higher incomes are assigned the lowest priority groups and may face more limited access to services.
Enrollment Timing
When you can sign up depends on the program. Medicaid and CHIP have no enrollment deadlines. You apply whenever you need coverage, and if you qualify, your coverage can begin right away or even retroactively in some states.
Medicare enrollment is more structured. Most people sign up during a seven-month window around their 65th birthday. If you miss it, you may face late-enrollment penalties.
For subsidized private plans on the ACA Marketplace (which aren’t technically public insurance but are publicly subsidized), open enrollment runs from November 1 through January 15. If you enroll by December 15, coverage starts January 1. Enroll between December 16 and January 15, and coverage begins February 1. Outside that window, you can only enroll if you experience a qualifying life event like losing other coverage, getting married, having a baby, or moving to a new area.
How the U.S. System Compares Globally
The U.S. is unusual in that its public insurance programs cover specific groups rather than the entire population. Most wealthy nations use one of three models to provide universal coverage.
- Government-run care (Beveridge model): The government funds and often directly provides healthcare through tax revenue. Great Britain, Spain, and New Zealand use this approach.
- Employer-based insurance with universal access (Bismarck model): Insurance is financed jointly by employers and employees through payroll deductions, but unlike U.S. private insurance, the plans are nonprofit and must cover everyone. Germany, France, Japan, and Switzerland follow this model.
- National health insurance: Private doctors and hospitals deliver care, but a single government-run insurance program pays for it, funded by taxes or premiums. Canada is the classic example. These systems tend to have lower administrative costs than the U.S. system but may use waiting lists or limits on covered services to control spending.
The U.S. system blends elements of all three models. Medicare resembles national health insurance. The VA system operates more like the Beveridge model, with government-employed providers. And employer-sponsored private coverage echoes the Bismarck approach, though without the universal mandate or nonprofit requirement. The result is a patchwork where your age, income, employment, disability status, and state of residence all determine which type of coverage, if any, you’re eligible for.