Deductible, Coinsurance, Out-of-Pocket Maximum: Which One Actually Caps Your Costs

A health plan quotes several numbers, and they do different jobs. Working out which one limits your exposure is the difference between comparing plans properly and comparing premiums.

The four terms

Premium. What you pay to hold the plan, every month, whether you use it or not. It is not affected by anything below.

Deductible. What you pay for covered services before the plan starts sharing costs. A $2,000 deductible means the first $2,000 of covered care is yours.

Copayment and coinsurance. How costs are split after the deductible. A copay is a fixed amount per service, say $30 for a visit. Coinsurance is a percentage, say 20% of the cost, with the plan paying the other 80%.

Out-of-pocket maximum. The most you can pay for covered services in a plan year. Once you reach it, the plan pays 100% of covered care for the rest of the year.

The out-of-pocket maximum is the number that matters

The deductible tells you when cost-sharing starts. The out-of-pocket maximum tells you where it stops, and that is the figure that describes your worst case.

Work an example through. Suppose a plan has a $2,000 deductible, 20% coinsurance, and a $7,000 out-of-pocket maximum, and you incur $50,000 in covered care.

You pay the first $2,000 as the deductible
Coinsurance then applies at 20%. On the next $25,000 of care, your 20% share is $5,000
At that point you have paid $2,000 plus $5,000, which is $7,000, your maximum
You reached it after about $27,000 of covered care
The remaining $23,000 is paid entirely by the plan

Your total for the year is $7,000 plus premiums, not $50,000 and not the $10,000 that 20% of everything would suggest. Coinsurance does not run forever; the maximum truncates it.

This is why a plan with a high deductible and a low out-of-pocket maximum can be safer than the reverse, and why comparing deductibles alone is the wrong comparison.

What does not count towards the maximum

The cap is narrower than it sounds. Typically excluded:

Premiums. These never count towards the out-of-pocket maximum
Out-of-network care, in many plans, or counted against a separate and higher limit
Services the plan does not cover at all. If it is not a covered benefit, the spending does not accumulate towards the cap
Costs above what the plan considers allowable for a service

That last group is the one that causes unpleasant surprises. The out-of-pocket maximum caps your share of covered, in-network care. It is not a cap on everything you might be billed in a bad year.

Reading a plan properly

Two plans, same insurer, very different shapes:

Plan A: low premium, $6,000 deductible, $8,500 out-of-pocket maximum
Plan B: higher premium, $1,000 deductible, $4,000 out-of-pocket maximum

If you use almost no care, Plan A wins on premiums alone. If you have a serious year, Plan B caps your exposure $4,500 lower. The right comparison is the total across a realistic year and a bad year: premiums for twelve months, plus what each plan would leave you paying.

The same logic as choosing a deductible applies here. You are deciding how much risk to keep rather than which number looks smaller.

The practical checks

Find the out-of-pocket maximum first, and treat it as the plan's real worst case
Check whether it is per person or per family, since family figures are usually higher
Check how out-of-network care is treated, and whether it has its own limit
Confirm your regular providers and prescriptions are in network and covered
Remember the year resets, so care spanning December and January can mean paying two deductibles

An out-of-pocket maximum only protects you if you can actually pay it. If yours is $7,000 and your savings are $500, the gap is the real problem, which is what an emergency fund is for.

The four terms in sequence

The confusion comes from treating these as four separate charges. They are four stages of one process, and they apply in order.

Stage	What you pay	When it applies
Premium	A fixed monthly amount	Always, claims or not
Deductible	100% of covered costs	Until the deductible is met
Coinsurance	A percentage, the plan pays the rest	After the deductible, until the maximum
Out-of-pocket maximum	Nothing further	Once reached, for the rest of the year

Copays sit slightly outside this sequence: they are flat fees for specific services, they often apply before the deductible is met, and depending on the plan they may or may not count toward the deductible. They almost always count toward the out-of-pocket maximum.

A full year, worked

Take a plan with a $2,000 deductible, 20% coinsurance, and a $7,000 out-of-pocket maximum. Suppose you incur $60,000 of covered costs.

Stage	Covered costs in this stage	You pay	Running total
Deductible	First $2,000	$2,000	$2,000
Coinsurance at 20%	Next $25,000	$5,000	$7,000
Maximum reached	Remaining $33,000	$0	$7,000

Your total for the year is $7,000 plus your premiums, no matter how far the costs run beyond $60,000. Whether the bill is $60,000 or $600,000, your exposure is the same.

That last point is the entire purpose of the out-of-pocket maximum, and it is the number that tells you what a bad year costs. The deductible tells you what a mild year costs; the maximum tells you what a catastrophe costs. When comparing plans, the maximum is the more important figure and it is usually the less prominent one.

Comparing two plans properly

A plan with a low premium and a high maximum is a bet on staying healthy. Here are two plans compared across three scenarios:

	Plan A	Plan B
Monthly premium	$250	$420
Deductible	$6,000	$1,500
Coinsurance	30%	20%
Out-of-pocket maximum	$9,000	$4,500

Year type	Plan A total	Plan B total
No care used	$3,000	$5,040
$5,000 of costs	$8,000	$7,740
Catastrophic year	$12,000	$9,540

Plan A wins if nothing happens. Plan B wins if something serious does. The crossover sits somewhere in the middle, and neither plan is simply better.

The right way to choose is to compute the worst case for each: premium times twelve, plus the out-of-pocket maximum. That is your true maximum exposure. Plan A's is $12,000; Plan B's is $9,540. If you could not absorb $12,000, Plan A's lower premium is not a saving, it is unhedged risk.

What does not count toward the maximum

This is where plans surprise people, because several large categories sit outside the cap entirely:

Premiums. You keep paying them after reaching the maximum
Out-of-network care, on many plans, or it counts toward a separate and much higher out-of-network maximum
Services the plan does not cover at all, which never count toward anything
Balance billing by an out-of-network provider for the amount above what the plan allows
Amounts above the plan's allowed charge for a service

The out-of-network point is the one that does the most damage. An in-network maximum of $7,000 offers no protection at all if care was received out of network, and in an emergency the choice of provider may not be yours. Federal protections restrict surprise billing in several situations, but they do not cover every case.

Family plans have two layers

Family coverage typically carries both an individual and a family deductible and maximum. One person's costs can satisfy their individual figure while the family figure remains unmet.

Check specifically whether your plan is embedded or aggregate:

Embedded: each person has their own deductible within the family total. One person reaching theirs starts receiving coinsurance even if the family total is not met
Aggregate: no benefits until the whole family deductible is met, even if that is one person's costs entirely

For a family where one member has significant medical needs, this distinction changes the cost of the year substantially.

Practical checks before choosing

Work out premium times twelve plus the out-of-pocket maximum for every plan offered. That is the worst case, and it is the only figure that compares plans honestly.
Confirm your regular doctors and hospitals are in network, and check again at renewal, since networks change annually.
Check whether the plan's out-of-network maximum exists and what it is.
Establish whether copays count toward the deductible, which varies.
If it is a family plan, find out whether it is embedded or aggregate.
Confirm your prescriptions are on the formulary, and at which tier.
Check whether the plan is HSA-eligible, if that matters to you.

Then hold the deductible in accessible cash, because a plan you cannot afford to use is not cover. See building an emergency fund and choosing an insurance deductible for how that reserve should be sized.

Sources

Current as of August 2026. Deductible, coinsurance and maximum figures are illustrative examples. Plan terms vary; read your own plan documents for the figures that apply to you.