What is coinsurance?
Quick answer
Coinsurance is a cost-sharing rule where the policyholder pays a set percentage of a covered cost, such as 20 percent, and the insurer pays the rest. In health plans it usually starts after the deductible is met; in property insurance the term also describes a rule about insuring enough of a building's value.
Last updated
Updated · By Robert Breen
Why it matters for a small business
Because it is a percentage, coinsurance can be small on a minor bill and large on a major one, which is why people are often surprised by it. A member who is used to a fixed copay may not expect to owe 20 percent of a hospital stay, even with good insurance.
The property version surprises business owners in a different way. Many commercial property policies require you to insure a minimum share of the property's value, and if you insure less, a claim can be paid at a reduced rate. Both versions are best explained with the actual policy numbers in hand. AI can turn those numbers into a plain example, provided someone checks the math.
In a real lesson: Reply Faster to Claim-Status Emails: ChatGPT for Independent Insurance Agencies
No Stepthrough lesson involves coinsurance. The Reply Faster: Claim-Status Emails lesson is the closest practice, because it is about telling a client exactly what share of a loss is theirs. Denise Harper's deer claim, handled through the made-up Stonebridge Insurance Agency, has a $500 comprehensive deductible that "comes out of the payment."
In the lesson, ChatGPT checks each claim in its draft against the numbered facts you pasted, and the deductible line passes because Facts 1 and 3 back it up.
A coinsurance explanation needs the same discipline plus arithmetic. Give the AI the plan's percentage, the deductible and the bill, ask it to show the calculation step by step, and check the result yourself before the email goes out.
Try this lesson free or read the step-by-step guide.
Common confusions
Coinsurance vs copay
A copay is a fixed dollar amount per service. Coinsurance is a percentage of the cost, so it changes with the size of the bill.
Coinsurance vs deductible
The deductible comes first and is paid in full by you. Coinsurance usually applies to costs after the deductible is met.
Tips
- Explain coinsurance with a worked example using the client's real numbers.
- For property policies, ask the agent whether a coinsurance clause applies and at what percentage.
- Have AI show its math so you can check each step.
Related terms
More Business terms
Where you use it: free lessons
Frequently asked questions
- How is coinsurance calculated?
- In a typical health plan, subtract any unmet deductible from the allowed cost, then multiply the rest by the coinsurance percentage. Plans differ, so check the plan summary.
- Does coinsurance ever stop?
- In most health plans, yes. Once you reach the out-of-pocket maximum for the year, the plan pays 100 percent of covered costs for the rest of that year.