Coinsurance Calculator

About this calculator

Coinsurance is the percentage split of a covered medical bill you share with your insurer after you've met your deductible — for example, an 80/20 plan means the insurer pays 80% and you pay 20% of the remaining cost — and it keeps applying to each bill until your total out-of-pocket spending for the year reaches your plan's out-of-pocket maximum, after which the insurer covers 100% of covered costs. It sits alongside deductibles and copays as one of the three main ways U.S. health plans split cost with the patient.

Patients use a coinsurance calculation to figure out roughly what they'll actually owe for a procedure or treatment before the bill arrives, and to understand at what point in the year their expenses shift from coinsurance-based cost-sharing to being fully covered because they've hit the out-of-pocket max — useful for budgeting elective procedures or comparing plan options during open enrollment.

This calculator takes your bill amount, deductible, coinsurance percentage and out-of-pocket maximum, and returns what you actually owe.