Deductible and Coinsurance Calculator

Estimate your share of a covered medical bill. Enter the fee (your plan's allowed amount), remaining deductible and your coinsurance percentage, then click Calculate.

What to enter in the calculator

Fee: Enter the allowed amount for the covered service, which may be lower than the provider's original charge. Use the amount from your insurer's estimate or explanation of benefits.
Remaining deductible: Enter how much of the applicable deductible you still need to meet before this bill. For example, a $1,500 deductible with $1,000 already credited leaves $500. Enter 0 if it has been met.
Coinsurance %: Enter the percentage you pay after the deductible. For an 80/20 split where your insurer pays 80%, enter 20. Coinsurance is a percentage; a copay is a fixed dollar charge.

Use dollar amounts of 0 or more and a coinsurance percentage from 0 to 100.

How deductible and coinsurance are calculated

The calculator applies the fee to your remaining deductible first. You pay that portion in full, then your coinsurance percentage of any fee left over.

Deductible portion = the smaller of the fee and remaining deductible.
Coinsurance portion = (fee − deductible portion) × (coinsurance % ÷ 100).
Amount owed = deductible portion + coinsurance portion.

Calculation example

These examples assume the service is subject to the deductible and then 20% coinsurance, with no copay or out-of-pocket limit affecting this bill.

Before meeting the deductible: With a $300 fee and $1,000 remaining deductible, the entire $300 goes toward the deductible. You owe $300, leaving $700 of deductible.

A bill that meets the deductible: With a $2,000 fee and $1,000 remaining deductible, you pay $1,000 toward the deductible plus 20% of the remaining $1,000. You owe $1,200 ($1,000 + $200).

After meeting the deductible: With a $2,000 fee and $0 remaining deductible, you pay 20% of $2,000. You owe $400.

Assumptions and limits of this estimate

This calculator estimates one covered, in-network bill that applies to a deductible followed by a single coinsurance rate. It does not determine whether a service is covered.

Out-of-pocket maximum: The calculator does not track this limit or your spending so far. If this bill brings you to your plan's out-of-pocket maximum, your share of covered in-network costs may be lower than the result.
Other charges: The result excludes premiums, copays, noncovered services, out-of-network rules and any charges above the allowed amount.
Plan-specific benefits: Some services are covered before the deductible, and some have separate deductibles or different coinsurance rates. Family plans may have individual and family deductibles. Use the benefit and remaining deductible that apply to this service.

Check your plan documents and insurer's explanation of benefits for the amount you actually owe.

Comparing insurance plans? Estimate your total annual cost with the Health Insurance Plan Comparison Calculator, which includes premiums and an out-of-pocket maximum.