What is health insurance?
An agreement to share the cost of care. Here is what the five key words mean, what actually sets the price, and why 26,698,044 people under 65 still have none.
Health insurance is an agreement to share the cost of medical care. You pay a fixed amount every month whether you use it or not; in return the insurer pays most of the bill when you do. The reason it exists in that shape is that medical costs are wildly unpredictable — most people spend very little in a given year, and a few spend an amount that would end them financially.
Source: US Census Small Area Health Insurance Estimates, 2024 release.
The five words that decide what you actually pay
Almost every argument about a health plan comes down to five numbers, and they trade against each other. A plan with a low one usually has a high another.
| Term | What it is | When you pay it |
|---|---|---|
| Premium | The monthly price of holding the plan | Every month, used or not |
| Deductible | What you pay yourself before the insurer starts paying its share | Early in the year, if you need care |
| Copay | A flat charge for a specific visit or prescription | At the point of care |
| Coinsurance | Your percentage of a bill after the deductible is met | After the deductible |
| Out-of-pocket maximum | The ceiling. Once you hit it the plan pays everything covered for the rest of the year | The point at which your spending stops |
The out-of-pocket maximum is the one people skip and the one that matters most, because it is the only number that answers "what is the worst year I could have". A plan with a cheap premium and a high maximum is a bet that you will not need much. That bet is fine right up until it is not.
Why the same plan costs different amounts
Price is set by where you live, how old you are, and whether you use tobacco. It is not set by your medical history — insurers cannot charge you more or refuse you for a pre-existing condition on a marketplace plan, which is the single biggest difference between this market and the one before 2014.
Geography does more work than most people expect. Insurers file prices county by county, so two people the same age on the same income can be offered different plans at different prices across a county line. That is why this site is built county by county rather than nationally — find yours.
What the government pays toward it
If you buy your own coverage and earn under $63,840 as a single person, a premium tax credit pays part of the premium directly to the insurer. It is not a rebate you claim later; it lowers the monthly bill. Above that income there is nothing — the cliff is a real edge, not a taper.
Nationally, 13,476,923 uninsured people sit inside the range that credit is built for. That is 50% of everyone under 65 without coverage — the majority of the problem is affordability among people who already qualify for help, not people who do not.
Where coverage comes from
Most people never buy health insurance directly: it arrives through a job, or through a public program. The routes are limited and mostly determined by your circumstances rather than your preference. Which one applies to you is a short question with a definite answer.
What the marketplace is · What plans cost · Coverage where you live