Deductible vs. copay vs. coinsurance: a worked example

Three terms, three different jobs

These are different from the premium you pay to keep coverage. Read the definitions from HealthCare.gov: deductible, copayment and coinsurance. Do not assume every service follows the same sequence.

A bill that crosses the deductible

This is an original hypothetical calculation, not a quote or an estimate for a particular treatment. Assume one covered, in-network service has an allowed amount of $900. Your deductible is $1,600 and $1,300 has already been credited toward it. This service is subject to that deductible, followed by 25% member coinsurance, with no separate copay. Assume you are not close enough to the applicable out-of-pocket limit for it to reduce this bill.

1. Find the remaining deductible: $1,600 minus $1,300 = $300.
2. Apply that first: $300 of the $900 allowed amount is your responsibility and completes the deductible.
3. Find the balance: $900 minus $300 = $600.
4. Apply coinsurance to that balance: 25% of $600 = $150.
5. Total your share: $300 + $150 = $450. The plan pays the other $450.

The two shares add back to the $900 allowed amount. Applying 25% to the entire $900 would miss the deductible still owed. Adding the full $1,600 deductible would ignore the $1,300 already credited. Neither shortcut produces the right result under these assumptions.

If the deductible had already been met, the same assumed service would cost you $225 in coinsurance, before considering the out-of-pocket limit. If more than $900 remained on the deductible, you would owe the full $900 allowed amount under this example's rules. The calculation follows the cost-sharing framework in HealthCare.gov's coinsurance explanation; your own plan determines the actual rules.

Can a copay apply before the deductible?

Yes, if that is how the plan covers the particular service. Some services are covered before you meet the deductible; other services may have a separate deductible. Family coverage can also involve individual and family thresholds. HealthCare.gov explains these deductible variations.

For example, if your plan specifically says an in-network primary-care visit has a $35 copay and the deductible does not apply, do not substitute the full visit cost just because your deductible is unfinished. That example does not establish what a lab test ordered during the visit costs. Check each service's benefit row and exceptions. Do not automatically add a copay and coinsurance together, or assume a copay reduces your deductible; ask how your plan treats each payment.

The out-of-pocket limit is a separate checkpoint

For covered in-network benefits, the applicable out-of-pocket maximum limits qualifying cost sharing during the plan year. After reaching it, the plan pays covered in-network benefit costs. Premiums, noncovered services, out-of-network care and charges above allowed amounts are not included in the Marketplace limit described by HealthCare.gov. Do not treat this as a cap on every expense you might face.

Return to the $450 member share above. If only $100 remained before the applicable limit, and all of this service's member cost sharing qualified toward it, the member share would instead be capped at $100. That is a different assumption from the main example. Ask the insurer for the current accumulator balance and how pending claims could affect it.

Use the plan document, not just the headline number

Start with the exact plan year's Summary of Benefits and Coverage (SBC), then use the full policy or insurer's explanation for unresolved details. The SBC is designed for comparing benefits and includes coverage examples. You can request it from your insurer or group health plan. HealthCare.gov: getting and using an SBC.

Before trying to calculate a service, write down these answers:

• Is the service covered, and are the provider and facility in this exact network?
• What allowed amount should the calculation use?
• Does the deductible apply to this benefit, and how much remains?
• Is the member charge a copay, coinsurance, or a stated combination?
• Are prescriptions or family members handled under different thresholds?
• What counts toward the applicable out-of-pocket limit?
• Are authorization, referral or separate billing questions still unresolved?

A useful message to the plan is: “For this service and provider, please identify the benefit category, deductible treatment, member cost sharing and applicable limit. Which details are estimates, and what could change the final amount?” Save the response with the plan name and date. For the broader decision, use our health insurance plan comparison guide. For Marketplace options and official assistance, start at HealthCare.gov.