Deductible, Copay, Coinsurance: Three Words, One Worked Example
Three cost-sharing words, one broken wrist, five bills. What each one does, in what order, and why covered does not mean free.
Three words, three different jobs, applied in an order. A deductible is an amount you pay first, in a plan year, before the plan starts sharing. A copay is a fixed amount for a particular service, and it often applies whether or not the deductible has been met. Coinsurance is a percentage of the allowed amount, and it applies after the deductible has been met. Sitting behind all three is a fourth idea that decides how big the arithmetic is: the allowed amount, which is the contracted price rather than what was billed.
On the practice claim below, $3,160.00 of charges have an allowed total of $1,850.00, so $1,310.00 is written off and never billed to anybody. Of what remains, the family's share is $1,460.00.
The practice plan
| Term | On this practice plan |
|---|---|
| Premium, employee share | $214.00 a month |
| Family deductible | $3,400.00 |
| Coinsurance | 20% after the deductible |
| Out-of-pocket maximum | $7,500.00 |
One convention runs through everything below, and it is the one people miss: only the allowed amount is ever divided. Copays skip the deductible but still climb toward the maximum. Premiums count toward neither.
The worked example: one broken wrist, five bills
| Service | Billed | Allowed | Written off | Family pays | Plan pays |
|---|---|---|---|---|---|
| Urgent care | $480.00 | $260.00 | $220.00 | $60.00 | $200.00 |
| X-ray | $610.00 | $340.00 | $270.00 | $340.00 | $0.00 |
| Orthopedist and cast | $1,240.00 | $760.00 | $480.00 | $760.00 | $0.00 |
| Follow-up and removal | $520.00 | $300.00 | $220.00 | $300.00 | $0.00 |
| Well-child visit | $310.00 | $190.00 | $120.00 | $0.00 | $190.00 |
| Totals | $3,160.00 | $1,850.00 | $1,310.00 | $1,460.00 |
Now read the five rows one at a time, because each one is teaching a different word.
The copay row
Urgent care was billed $480.00 and allowed $260.00. The family paid a fixed $60.00 copay and the plan paid the other $200.00, per policy terms. The copay skipped the deductible entirely and still counts toward the $7,500.00 ceiling.
The rows that shock people
The x-ray, the orthopedist and the follow-up all landed while the deductible was unmet, so the family paid the allowed amount in full each time and the plan paid nothing. That is not a coverage failure. It is what a deductible is. Covered does not mean free. It means the plan's rules apply to the charge, and one of those rules is that you pay first up to a stated amount.
After those three the running deductible stands at $1,400.00 of $3,400.00, leaving $2,000.00. If a second event lands before the plan year rolls over, it starts from there rather than from zero.
The row that costs nothing
The well-child visit was billed $310.00, allowed $190.00, and the family paid $0.00. In-network preventive services required under federal rules carry no cost sharing on most plans, and the plan paid all $190.00, per policy terms and your own plan documents. healthcare.gov explains which services that covers.
The order these three apply in
Sequence is what makes the arithmetic predictable, and the sequence is nearly always the same.
- A price is set by contract. The allowed amount, negotiated before you walked in.
- Copays apply where the plan says they do, often regardless of the deductible.
- The deductible absorbs allowed charges until it is met.
- Coinsurance splits what comes after, between you and the plan.
- The out-of-pocket maximum stops the counting once your covered share reaches it.
Every bill you will ever receive is somewhere in that list. Working out which step a charge is at answers most questions about it without any further arithmetic, and the running deductible figure your plan publishes tells you which step you are on.
Where coinsurance actually starts
Coinsurance is the word that has not appeared in the arithmetic yet, because the deductible was never met on this claim. If it had been, the next $100.00 of allowed charges would split $20.00 to the family and $80.00 to the plan, at 20%.
That is the practical distinction. A copay is a fixed amount and it does not care what the service cost. Coinsurance is a share and it cares very much, because 20% of a small bill and 20% of a very large one are completely different amounts of money. Which is why the out-of-pocket maximum exists at all.
Why the same treatment costs two households different amounts
Not because one was charged more. The billed figures can be identical and the outcomes completely different, for three reasons that are all visible on the documents.
Where each household is in its deductible. The same $760.00 charge is paid in full by a household with a standing deductible and split by one that has met it.
What the plan's contracted price is. Two plans can have different allowed amounts for the identical service, which changes the number everything downstream is calculated on.
Whether the provider is in network. Out of network there is often no agreed price and no required write-off, so the arithmetic starts from a much larger number.
Together those explain nearly every conversation that begins with somebody else paid less for the same thing. Usually both people are describing their documents accurately.
The allowed amount is the whole game
Look at the write-off column again. $1,310.00 of charges vanished before anybody's arithmetic began, because in network the provider has signed an agreement with the plan naming a price for each service. When the claim is priced, the difference between the charge and that contracted price is written off. Nobody bills anyone for it. It was negotiated before you walked in.
Out of network no agreed price exists, so no write-off is required and a provider may bill the balance. Federal rules limit balance billing in certain situations, including many emergencies. That is a specific and important carve-out and the rules for it are published at cms.gov.
How to read an explanation of benefits
Left to right, it answers four questions: what was charged, what the contract allowed, what the plan paid, and what may be left for you. Beside those sit the codes, including the amount applied to the deductible and any remark codes.
It is an accounting, not a bill. That single fact removes a great deal of unnecessary panic, because the document that looks most alarming in the envelope is usually the one that is not asking for money.
Which numbers to write down before you need them
- Your deductible, and how much of it is met right now. Most plans show a running figure.
- Your coinsurance share. The percentage that applies once the deductible is met.
- Your out-of-pocket maximum, and what counts toward it in your own plan documents.
- Whether the plan year matches the calendar year. This decides whether a January event starts from zero.
- Which copays apply to which services, because they often differ by setting.
Five numbers on one piece of paper. That is the difference between reading a bill and guessing at one, and it is worth ten minutes in a quiet week rather than in a bad one.
Why the cash cushion matters here
The deductible is, in practice, a planned expense that arrives without a date. A household carrying a $3,400.00 deductible has agreed to be able to produce that money at short notice, and the whole point of a cushion is being the thing that produces it. Sizing a starter cushion uses the same logic: price the likeliest shocks, then hold the larger of one bare month or the tallest one.
The rest of the vocabulary, and where each number lives on the document, is on the four numbers page. And when a claim actually happens, the sequence is worth knowing in advance, which is what filing a claim step by step is for.
Most plans publish a running figure. Knowing it turns the next bill from a mystery into arithmetic you can check.
Going further
How Insurance Works follows this claim line by line and then does the same for auto, home, life and income cover on the same household. It names no insurer and no plan, and every figure in it is computed in code rather than typed.
For what is required of plans and what counts as preventive, healthcare.gov is the authority. For your own cover, your plan documents and a licensed agent are the right sources.
Questions people actually ask
What is the difference between a copay and coinsurance?
A copay is a fixed amount for a service. Coinsurance is a share of the allowed amount, so it moves with the size of the bill. On the practice plan here, an urgent care visit carries a $60.00 copay while coinsurance is 20% of whatever the allowed amount turns out to be.
Why did I pay the full amount for something that was covered?
Because the deductible had not been met. On the practice claim, an x-ray with an allowed amount of $340.00 was paid entirely by the family and $0.00 by the plan, because the deductible of $3,400.00 was still standing. Covered does not mean free; it means the plan's rules apply to it.
What is an allowed amount?
The price set by a contract between the plan and the provider, signed before you were ever hurt. On the practice claim, a charge of $1,240.00 had an allowed amount of $760.00, so $480.00 was written off and nobody bills anyone for it. Only the allowed amount is divided between you and the plan.
What does the out-of-pocket maximum do?
It caps what you pay in a plan year for covered services under the plan's rules. On the practice plan that ceiling is $7,500.00. Copays and the deductible generally climb toward it; premiums generally do not. What counts toward yours is written in your own plan documents.
Is this insurance advice?
No. This is general financial education using an invented practice plan. It is not financial advice, not insurance advice, and not a recommendation about any plan. Cover always depends on the terms of a real policy and your own plan documents, and healthcare.gov and your state insurance department are the right authorities.