The percentage of the costs of covered healthcare services you pay out-of-pocket (20%, for example) after you've met your deductible.
Let's say your health insurance plan's allowed amount for a doctor’s visit is $100 and your plan's coinsurance is 20% and:
- You've paid your deductible: You pay 20% of $100, or $20. The insurance company pays the rest.
- You haven't met your deductible: You pay the full allowed amount, $100.
Generally speaking, plans with low monthly premiums have higher coinsurance, and plans with higher monthly premiums have lower coinsurance.