Coinsurance after deductible is the percentage of the costs of a covered healthcare service that you pay after you have paid your deductible. For example, if your health insurance plans deductible is $1,000 and your coinsurance is 20%, you will pay $200 (20% of $1,000) for a covered healthcare service, and your insurance company will pay the rest. If you havent met your deductible, you will pay the full allowed amount for the service. Coinsurance applies after you have met your deductible, and it is a way of sharing the cost of eligible expenses with your insurance carrier. The percentage of coinsurance can vary depending on the plan, and plans with low monthly premiums usually have higher coinsurance, while plans with higher monthly premiums have lower coinsurance.