Coinsurance
In health insurance: the percentage of covered costs a policyholder pays after meeting the deductible and before reaching the out-of-pocket maximum. In property insurance: a clause requiring the insured to maintain cover at a minimum percentage of the property's replacement value or face a proportional reduction in claim payouts.
Coinsurance in health insurance
After you meet your deductible, the insurer pays its share and you pay yours. A plan with 20% coinsurance means you pay 20 cents of every covered dollar until you hit your out-of-pocket maximum — at which point the insurer pays 100%.
Our guide to coinsurance and copays has worked examples and a comparison with fixed copays.
Coinsurance in property insurance
In home and commercial property insurance, a coinsurance clause sets the minimum percentage of replacement value at which you must insure your property (typically 80–90%). If your policy limit falls short, the insurer calculates a proportional payout: (your limit ÷ required limit) × loss. Under-insurance by 20% can cost you 20% of every claim payout.
Coinsurance FAQ
Frequently asked questions
- An 80/20 split means the insurer pays 80% of covered costs and you pay 20% — after your deductible is met and until you reach your out-of-pocket maximum. The HealthCare.gov coinsurance definition explains how this applies in US marketplace plans.
- No. A copay is a fixed dollar amount per service visit (e.g. $30 per GP visit). Coinsurance is a percentage of the total cost. For a $400 specialist visit, a $40 copay costs $40; 20% coinsurance costs $80. See our guide to coinsurance and copays for a full comparison.
- In home and commercial property insurance, a coinsurance clause requires you to insure your property to at least a specified percentage of its replacement cost (commonly 80%). If you under-insure, the insurer may proportionally reduce any claim payout. The Insurance Information Institute explains how this applies to property claims.