You have a health plan, a card full of jargon, and no idea what your next doctor's visit will cost. US health insurance has five moving parts, and they apply in a fixed order — once you know the order, any bill or explanation of benefits becomes readable.
You and the insurer split the bill in stages
Every covered bill is split between you and your insurer, and the split changes as your spending for the year grows. Early in the year you pay most of each bill yourself. Past one line the insurer starts sharing. Past a second line the insurer pays everything. The five terms are the names of those stages and the lines between them.
| Term | What it is | Who you pay |
|---|---|---|
| Premium | A fixed monthly cost just to have coverage | The insurer, every month |
| Deductible | What you pay before the insurer shares costs | Providers, until you reach it |
| Copay | A flat fee for a specific service | The provider, at the visit |
| Coinsurance | Your percentage of the bill after the deductible | The provider, after the insurer pays its share |
| Out-of-pocket maximum | The yearly ceiling on what you can pay | Nobody past this line — the insurer covers 100% |
Premium: the cost of being covered at all
The premium is what you pay every month whether or not you see a doctor. If your plan comes through work, your share comes straight out of each paycheck, usually before taxes, which is why it lowers both your gross income and your taxable income on the pay stub. Treat it as a fixed line in your budget, like rent — the budget calculator has a slot for it.
The premium buys access to everything else: the insurer's negotiated prices, the cost-sharing, and the ceiling on your spending. It does not count toward your deductible or your out-of-pocket maximum.
Deductible: the amount you pay first
Your deductible is the amount you pay for covered care before the insurer starts sharing. With a $1,500 deductible, the first $1,500 of covered bills in the year is yours. You still get the plan's negotiated rate on those bills — you just pay all of it.
Two things sit outside the deductible on most plans. Preventive care — your annual checkup, most vaccines, many screenings — is covered in full from day one. And services with a copay usually charge the copay instead of counting against the deductible.
Copay vs. coinsurance: two ways to share a cost
A copay is a flat dollar fee for a specific service: $30 to see your primary doctor, $60 for a specialist, $15 for a generic prescription. It's the same number every time, whatever the visit's full price.
Coinsurance is a percentage. After you meet the deductible, you and the insurer split the rest of each bill by a set ratio — commonly 20% you, 80% insurer. The dollar amount moves with the size of the bill: 20% of a $200 visit is $40, but 20% of a $5,000 procedure is $1,000.
| Copay | Coinsurance | |
|---|---|---|
| Form | Flat dollar amount | Percentage of the bill |
| When it applies | Usually before the deductible | After the deductible is met |
| Predictability | Same every time | Scales with the bill |
| Example | $30 office visit | 20% of a $3,000 bill |
Out-of-pocket maximum: the ceiling that protects you
The out-of-pocket maximum is the most you can pay in a plan year for covered, in-network care. Your deductible, copays and coinsurance all count toward it; premiums do not. Once you hit it, the insurer pays 100% of covered in-network care for the rest of the year. This ceiling is the reason a serious illness has a worst-case cost instead of an unlimited one — and it is the first number to compare when you choose a plan at open enrollment.
For 2025, a high-deductible health plan (the kind that lets you fund an HSA) must have a deductible of at least $1,650 for self-only coverage or $3,300 for family coverage, and its out-of-pocket maximum can be no more than $8,300 self-only or $16,600 family. Those IRS figures are the outer edges; your plan's own numbers are printed in its summary of benefits.
The order, every time
For any covered in-network bill: check whether a flat copay applies; if not, pay whatever deductible is still unmet; split the rest by coinsurance; stop paying once you reach the out-of-pocket maximum. Premiums sit outside this flow entirely. Hold those five terms in that order and the explanation of benefits the insurer sends after each visit stops looking like a foreign language. Your deductible is also the first number to size your emergency fund around — Elena's $1,500 is a bill she could receive in any month.