Coinsurance is your share of a cost expressed as a percentage. If the plan pays 80% and you pay 20%, that 20% is coinsurance, and it usually kicks in after the deductible is satisfied.
The difference from a copay matters more than it looks. A copay is knowable in advance: $50 is $50. Coinsurance is a percentage of a number you don’t know yet — and in a hospital that number can be large. Twenty percent of an imaging bill is a different animal from twenty percent of an office visit.
Where it bites hardest: imaging, surgery, hospital stays, specialty drugs. Anything where the underlying price is high and variable.
How to bound it: the out-of-pocket maximum is the ceiling on your combined deductible, copays and coinsurance for in-network care in a plan year. Out-of-network care often doesn’t count toward it, which is how people end up past the “maximum” and still paying.
Also called: cost sharing percentage. Reference: Coinsurance on Wikipedia — general definition, not New York specifics.
More in Glossary of health coverage and billing terms
- Explanation of benefits (EOB) — The statement from your insurer showing what was billed, what was paid, and what you may owe. It is not a bill.
- Chargemaster — A hospital's internal list price for every service. Almost nobody pays it — except the uninsured who don't ask.
- Charity care — The hospital financial assistance every New York hospital is legally required to run.
This page explains how the system works. It is not medical advice. More.