Decode the system

Deductible, Copay, Coinsurance, Out-of-Pocket Max - With Real Math

Four terms that decide what every visit costs you, explained with a worked example that follows one person through an entire plan year.

Current as of August 23, 2026 Decode the system

Four words do almost all the work in a health plan, and they are easy to confuse because three of them sound like the same idea. Here is the shortest accurate version:

Premium - what you pay to have coverage, whether or not you use it
Deductible - what you pay before the plan starts paying
Copay / coinsurance - what you keep paying after the deductible, per service
Out-of-pocket maximum - the ceiling, after which the plan pays everything covered

The most important sentence in that list: your premium never counts toward any of the other three. It is money out of your pocket, but the plan does not treat it as cost sharing. Neither does anything the plan does not cover.

A year in the life of one deductible

Meet a plan with a $2,000 deductible, 20% coinsurance, a $30 primary care copay, and a $7,000 out-of-pocket maximum. Everything below is in-network.

January - annual physical, billed $310. You pay $0. The ACA-listed preventive services are covered without cost sharing at in-network providers on non-grandfathered plans, and they do not touch the deductible. The catch: a checkup that turns into discussing a specific problem can be billed as two visits - see why a free physical can generate a bill. Deductible progress: $0.

March - sore knee, primary care visit. You pay the $30 copay. On many plans, copays do not count toward the deductible but do count toward the out-of-pocket maximum. Check your plan documents; this varies more than anything else on this page. Deductible progress: $0. Out-of-pocket: $30.

April - MRI, billed $2,400, allowed amount $900. You have not met your deductible, so you pay the allowed amount, not the billed amount: $900. The other $1,500 is a contractual write-off and never becomes your problem. Deductible progress: $900 of $2,000. Out-of-pocket: $930.

June - outpatient procedure, allowed amount $4,000. The first $1,100 finishes your deductible. The remaining $2,900 is shared: you pay 20%, or $580. Total for the day: $1,680. Deductible: met. Out-of-pocket: $2,610.

September - hospital admission, allowed amount $28,000. Deductible is done, so it is straight coinsurance: 20% of $28,000 is $5,600. But your out-of-pocket maximum is $7,000 and you are already at $2,610. You only have $4,390 of room left. You pay $4,390. The plan pays the rest. Out-of-pocket: $7,000 - maximum reached.

October through December - everything covered and in-network. You pay $0. Not a reduced amount. Zero.

Total for the year: $7,000 in cost sharing, plus twelve months of premiums, which were never part of this arithmetic at all.

The parts that trip people up

“I met my deductible, so everything is free now.” No - meeting the deductible moves you from paying 100% to paying your coinsurance share. Free comes at the out-of-pocket maximum, which is a different and much higher number.

Family deductibles have two layers. Most family plans have an individual deductible embedded inside the family one. A single family member usually cannot be charged more than the individual limit even if the family total is not met. If a family member is being billed past the individual amount, ask why.

Copays are the inconsistent one. Whether a copay counts toward the deductible, the out-of-pocket maximum, both, or neither is a plan-by-plan decision. Your Summary of Benefits and Coverage says which. It is the single most useful page in your plan documents.

Out-of-network has its own everything. Separate deductible, separate coinsurance percentage, and often a separate and much higher out-of-pocket maximum - or none at all. Progress on one side does not transfer to the other.

Non-covered services count for nothing. If your plan excludes a service, paying for it does not move your deductible, does not move your out-of-pocket maximum, and does not appear on an EOB in a way that helps you.

The ceilings for 2026

Federal rules cap how high cost sharing can go, though your specific plan may set lower limits.

Limit	Self-only	Family
ACA maximum out-of-pocket (marketplace and most job-based plans)	$10,600	$21,200
HDHP minimum deductible (to qualify for an HSA)	$1,700	$3,400
HDHP maximum out-of-pocket	$8,500	$17,000
HSA contribution limit	$4,400	$8,750

The HSA catch-up contribution for people 55 and older is an additional $1,000. Note that the HDHP out-of-pocket cap is lower than the general ACA cap - a plan cannot be HSA-eligible unless it keeps your exposure under the tighter number. More on which account to use in our guide to HSAs, FSAs, and HRAs.

The one calculation worth doing before you enroll

Add twelve months of premiums to the out-of-pocket maximum. That is your worst realistic year under the plan, and it is the only number that lets you compare a low-premium, high-deductible plan against a high-premium, low-deductible one honestly.

Then do it again assuming you use almost nothing. Those two numbers bracket your real exposure. Comparing monthly premiums alone tells you almost nothing, which is precisely why premiums are what gets advertised.

Numbers on your own EOBs will not always match your mental math, and that is worth investigating rather than accepting - start with how to read an EOB.

Sources

Figures and rules on this page are current as of August 23, 2026. Dollar limits and deadlines change - check the linked source before you rely on a number.

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