What Is an EOB? Explanation of Benefits Defined and Decoded

EOB Definition: What Does EOB Stand For?

EOB stands for Explanation of Benefits. It is a document sent by your health insurance company after you receive medical care. It explains what your provider charged, what your insurance paid, and what you may owe. It is not a bill.

When Do You Receive an EOB?

Typically 2-4 weeks after care is received and a claim is filed. Most insurers also make EOBs available in your online account portal faster than paper mail.

What Is in an EOB?

Member information — Name, member ID, group number
Provider information — Who provided the care
Date of service — When you received care
Services billed — Each procedure by CPT code and description
Billed vs. allowed amount — Full price vs. negotiated rate
Plan paid — What insurance covered
Member responsibility — Your deductible, copay, coinsurance
Claim status — Approved, denied, or pending

Key EOB Terms

Allowed Amount: The negotiated rate your insurer pays in-network providers. Lower than billed amount.
Deductible: Amount you pay before insurance kicks in. Tracked on your EOB year-to-date.
Coinsurance: Your percentage share after deductible (e.g., 20% in an 80/20 plan).
Out-of-Pocket Maximum: After this amount, insurer covers 100% of covered costs for the year.
Denial Code: Reason code when a service is not covered (e.g., CO-4 wrong procedure code, PR-1 deductible not met).

How Long to Keep EOBs?

At least 1 year, ideally 3-7 years. Essential for HSA/FSA reimbursement, disputing bills, disability applications, and tracking ongoing treatment.

Processing EOBs at Scale