What is coinsurance on a health insurance plan?
Coinsurance is the percentage of the cost of a covered health service you pay after you have met your deductible — for example, with 20% coinsurance on a $200 covered service you pay $40 and the ACA plan pays $160, per HealthCare.gov (2026).
More on this topic: health insurance marketplace
What the government has said, on the record
Here's how a federal official described it, on the record:
“The percentage of costs of a covered health care service you pay (20%, for example) after you've paid your deductible.”
— Centers for Medicare & Medicaid Services (HealthCare.gov), Centers for Medicare & Medicaid Services (U.S. Department of Health & Human Services), HealthCare.gov Glossary, Coinsurance (source)
Editor's note: Official HealthCare.gov (CMS) definition. The 20% is an illustrative example; confirm current rules at HealthCare.gov.
Who said this
Centers for Medicare & Medicaid Services (HealthCare.gov) · Centers for Medicare & Medicaid Services (U.S. Department of Health & Human Services)
Also asked as
- What does coinsurance mean?
Sources
Last verified: 2026-07-19