Enter the allowed amount and the plan’s coinsurance percentage to split the bill between patient and insurance — with common splits compared.
What coinsurance is
Coinsurance is the percentage of the allowed amount — never the billed charge — that the patient owes after the deductible is met. A “20% plan” means the patient pays a fifth of every allowed dollar and the plan pays the rest. Enter the two numbers and this calculator splits them, with the common 10/30/50 splits shown for comparison.
How to use it
- Enter the allowed amount from the fee schedule or EOB.
- Enter the plan’s coinsurance percentage.
- Read the patient and insurance shares.
The formula
A worked example
A $200 allowed amount at 20% coinsurance is $40 patient / $160 plan. The classic mistake is taking the percentage of the billed charge: 20% of a $350 charge would wrongly collect $70 — $30 more than the patient owes, and exactly the kind of over-collection that turns into refund work later. Percentage of allowed, always.
Estimates only — payer contracts, plan documents, published fee schedules and the EOB are the source of truth, and nothing here is billing, legal or medical advice. The calculator runs entirely in your browser: no patient data is entered, transmitted or stored.