What Is Coinsurance?
Coinsurance is the percentage of a covered medical bill you pay after meeting your deductible — commonly 20% under U.S. plans, with the insurer paying 80%. It applies to larger services like hospital stays and surgeries, and your share stops once you hit the out-of-pocket maximum for the year.
Why it matters
Coinsurance is why a big claim can still cost you a meaningful slice — but a capped out-of-pocket maximum prevents catastrophe.
Common confusion
Coinsurance is a percentage; a copay is a flat fee. Both usually count toward the out-of-pocket max but not always toward the deductible.
Frequently Asked Questions
What is the out-of-pocket maximum?
The most you pay in a year for in-network covered care (deductible + copays + coinsurance). For 2026 the ACA limits are roughly $9,200 individual / $18,400 family, inflation-adjusted.
Does coinsurance apply to every visit?
Only after the deductible is met, and only for services not covered by a flat copay under your plan’s schedule.