The percentage of costs of a covered health care service you pay (20%, for example) after you’ve paid your deductible.
Let’s say your health insurance plan’s allowed amount for an office visit is $100 and your coinsurance is 20%.
- If you’ve paid your deductible: You pay 20% of $100, or $20. The insurance company pays the rest.
- If you haven’t met your deductible: You pay the full allowed amount, $100.
Example of coinsurance with high medical costs
Let’s say the following amounts apply to your plan and you need a lot of treatment for a serious condition. Allowable costs are $12,000.
- Deductible: $3,000
- Coinsurance: 20%
- Out-of-pocket maximum: $6,850
You’d pay all of the first $3,000 (your deductible).
You’ll pay 20% of the remaining $9,000, or $1,800 (your coinsurance).
So your total out-of-pocket costs would be $4,800 — your $3,000 deductible plus your $1,800 coinsurance.
If your total out-of-pocket costs reach