2026 Guide

What Is an EOB? How to Read One

EOB means the statement your insurer sends explaining how it processed a medical claim. Here is a plain-English guide to what it is and how to read every field.

What is an EOB?

An Explanation of Benefits (EOB) is the document your health insurer sends after processing a claim. It is NOT a bill. It shows what the provider billed, the amount your plan allowed, what the insurer paid, and what portion is your responsibility. Reviewing it helps you catch billing and coverage errors before you pay.

Who sends an EOB, and when?

Your health-insurance carrier issues an EOB after a provider submits a claim — typically within a few weeks of a visit.

How to read an EOB, field by field

Patient & provider

Who received care and the doctor, hospital, or facility that billed.

Claim number & service date

The insurer’s reference for the claim and when the service occurred.

Procedure (CPT) codes

Standardized codes describing each service performed.

Billed vs. allowed amount

What the provider charged vs. the negotiated amount your plan permits.

Insurance paid

The portion your plan paid the provider.

Patient responsibility

Your share — copay, coinsurance, or deductible — the amount you may owe.

Denial / adjustment codes

Reason codes explaining any amount that was not covered.

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What to double-check

⚠An EOB is not a bill — do not pay from it; wait for the provider’s statement and compare.
⚠The "patient responsibility" on the EOB should match the provider’s bill; mismatches are worth disputing.
⚠Denial codes often indicate a fixable issue (wrong code, missing referral) rather than a true non-covered service.

Frequently asked questions

Is an EOB a bill?

No. An EOB explains how your insurer processed a claim. The bill comes separately from the provider.

What does "allowed amount" mean on an EOB?

The allowed amount is the maximum your plan will pay for a service under its negotiated rates — often less than the billed charge.

What should I do if my EOB and my medical bill do not match?

Contact the provider’s billing office and your insurer; a mismatch often signals a coding or processing error.