Copay, Deductible, and Out-of-Pocket Maximum: Definitions and Impact

Three cost-sharing terms — copay, deductible, and out-of-pocket maximum — govern how medical expenses are divided between a health plan and the person enrolled in it. Misunderstanding any of these figures can produce unexpected bills, deferred care, or unresolved debt. This page defines each term, explains how the three interact within a plan year, and identifies the regulatory boundaries set by federal law, primarily through the Affordable Care Act and implementing rules issued by the Centers for Medicare & Medicaid Services (CMS).

Definition and scope

Copay (copayment): A fixed dollar amount paid at the point of service, regardless of the total charge. Under rules implementing the Affordable Care Act (42 U.S.C. § 18022), a copay is one permissible form of cost sharing for covered essential health benefits (EHBs). A primary care visit copay is commonly structured as a flat fee — for example, $30 per visit — while specialist visits frequently carry a higher flat fee.

Deductible: The amount a covered individual must pay out of pocket for covered services before the health plan begins paying its share. The ACA's essential health benefits framework establishes that deductibles apply separately from premiums and reset each plan year. For marketplace plans sold through Healthcare.gov in 2024, CMS set the maximum deductible for self-only coverage at $9,450 for high-deductible-compatible plans under Health Savings Account (HSA) rules established by the IRS (IRS Revenue Procedure 2023-23).

Out-of-pocket maximum (OOPM): The statutory ceiling on total cost sharing in a plan year for covered in-network services. Once a covered individual reaches the OOPM, the insurer must pay 100 percent of covered costs for the remainder of that year. For 2024 marketplace plans, the ACA mandated OOPM limits of $9,450 for self-only coverage and $18,900 for family coverage (CMS, Notice of Benefit and Payment Parameters for 2024).

These three structures are distinct in mechanism but accumulate toward the same annual spending cap. For a full orientation to how plan types intersect with these figures, see Health Insurance Coverage Types.

How it works

Cost sharing in a standard plan year follows a sequential progression:

  1. Pre-deductible phase: The covered individual pays the full negotiated rate for most covered services (excluding preventive care, which must be covered at $0 cost sharing under 42 U.S.C. § 300gg-13) until the deductible is satisfied.

  2. Co-insurance phase: After the deductible is met, the plan pays a percentage of costs (typically 70–80 percent for silver-tier marketplace plans) and the enrollee pays the remainder as coinsurance. Copays may apply simultaneously or replace coinsurance depending on the plan design.

  3. Post-OOPM phase: Once total cost sharing — including deductible payments, copays, and coinsurance — reaches the out-of-pocket maximum, the plan covers 100 percent of covered in-network costs for the balance of the plan year.

Premiums, out-of-network charges above the allowed amount, and non-covered services do not count toward the OOPM under standard ACA-compliant plans. The Explanation of Benefits (EOB) document issued after each claim tracks how much of the deductible and OOPM has been applied.

Embedded vs. aggregate deductibles (family coverage):

The IRS and CMS have issued separate rules governing how high-deductible health plans (HDHPs) paired with HSAs must handle embedded vs. aggregate designs, specifically that an embedded individual deductible in a family HDHP cannot be lower than the statutory minimum HDHP deductible (IRS Notice 2004-50).

Common scenarios

Scenario A — Routine office visit:
A plan carries a $40 copay for primary care visits and a $1,500 individual deductible. If a patient visits a primary care physician for a non-preventive complaint, the $40 copay applies regardless of where the patient stands relative to the deductible, because the plan has structured copays to apply instead of deductible accumulation for office visits. This is a plan-design choice, not a federal requirement. Reviewing the prior authorization process is also relevant when specialist referrals follow.

Scenario B — Hospitalization with a high deductible:
A patient with a $3,000 deductible is admitted for a procedure with a $12,000 total negotiated cost. The patient pays the first $3,000 (satisfying the deductible), then coinsurance (for example, 20 percent of the remaining $9,000, equaling $1,800), for a total patient liability of $4,800 — assuming this does not exceed the OOPM. For context on facility billing, see Medical Billing and Coding Basics.

Scenario C — Family plan aggregate deductible:
A family of four has a $6,000 aggregate deductible. Three family members each incur $1,500 in claims, collectively meeting the $4,500 threshold. A fourth member's $2,500 surgery triggers the remaining $1,500 of the aggregate, at which point the plan begins covering all four members' costs at the coinsurance rate.

Scenario D — Out-of-network services:
Federal protections under the No Surprises Act, enacted as Division BB of the Consolidated Appropriations Act, 2021 (Pub. L. 116-260, enacted December 27, 2020), limit certain surprise billing situations — including restrictions on balance billing for emergency services and certain non-emergency services at in-network facilities — but standard out-of-network charges do not count toward the in-network OOPM. The Consolidated Appropriations Act, 2021 was signed into law on December 27, 2020, with No Surprises Act provisions taking effect for plan years beginning on or after January 1, 2022. See Surprise Medical Billing Protections and In-Network vs. Out-of-Network Providers for the full regulatory scope.

Decision boundaries

Several regulatory and plan-design boundaries determine how these cost-sharing mechanisms apply:

Preventive services carve-out: Under 42 U.S.C. § 300gg-13, ACA-compliant plans must cover a defined list of preventive services — including those rated A or B by the U.S. Preventive Services Task Force (USPSTF) — with zero cost sharing, meaning no copay and no deductible applies. See Preventive Care Services Covered for the full enumeration.

Grandfathered plan exemptions: Plans that existed on March 23, 2010 and have maintained grandfathered status under 45 C.F.R. § 147.140 are not subject to the OOPM cap or the preventive services zero-cost-sharing rule, creating a material distinction between grandfathered and non-grandfathered plan obligations.

Medicaid and CHIP cost sharing: Medicaid programs operate under a separate federal cost-sharing framework defined in 42 U.S.C. § 1396o. Cost sharing for Medicaid beneficiaries at or below 100 percent of the federal poverty level is limited to nominal amounts; cost sharing is prohibited entirely for certain services and populations. Medicaid Eligibility and Enrollment and Children's Health Insurance Program (CHIP) carry details on those frameworks.

Medicare: Medicare Part A and Part B use deductible and coinsurance structures that do not follow the ACA OOPM framework. Medicare does not impose a statutory out-of-pocket maximum for Parts A and B, though Medicare Advantage (Part C) plans are required to establish OOPMs. The Medicare Parts A, B, C, D Explained page covers those distinct structures.

Financial assistance intersection: Subsidized marketplace enrollees with incomes between 100 and 250 percent of the federal poverty level may qualify for cost-sharing reduction (CSR) subsidies under 42 U.S.C. § 18071, which lower the effective deductible and OOPM when a silver-tier plan is selected. Patient Financial Assistance Programs provides further reference on CSR eligibility and application.

References

📜 10 regulatory citations referenced  ·  ✅ Citations verified Feb 26, 2026  ·  View update log

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