Run the full cost-share waterfall: allowed amount through remaining deductible, copay, coinsurance and the out-of-pocket maximum, in the right order.
The waterfall, in the right order
Patient responsibility isn’t one number — it’s a sequence. The allowed amount first absorbs any remaining deductible; a copay applies where the plan has one; coinsurance then splits what’s left; and the out-of-pocket maximum caps the total. Getting the order wrong is the most common estimation error at the front desk, and it’s exactly what this calculator sequences correctly.
How to use it
- Enter the allowed amount for the service.
- Enter the patient’s remaining deductible (from eligibility verification).
- Add the copay and coinsurance percentage from the plan.
- Enter the remaining out-of-pocket max — it caps everything.
The sequence
A worked example
Allowed $180 against a $50 remaining deductible at 20% coinsurance: the patient pays the $50 deductible, then 20% of the remaining $130 — $26 — for a total of $76, with insurance paying $104. If the patient’s remaining out-of-pocket max were only $60, the patient share caps there and insurance absorbs the rest — which is why the OOP field changes answers late in the plan year.
Estimates only — payer contracts, plan documents and the EOB are always 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.