What Is an Explanation of Benefits (EOB) and How Do You Read One?
An Explanation of Benefits is not a bill — but it tells you exactly what your insurance paid and what you owe. Here's how to read every line of it.
You visit the doctor, and a few weeks later two things arrive in the mail: a bill from the provider, and a confusing document from your insurance company called an Explanation of Benefits — or EOB. Most people ignore the EOB. That's a mistake.
Your EOB is one of the most important documents in your healthcare financial life. Here's how to understand every part of it.
What is an EOB?
An Explanation of Benefits is a statement from your health insurance company that explains how a medical claim was processed. It is not a bill. It's a record of what your insurer paid, what they didn't pay, and what — if anything — you owe your provider.
You'll receive an EOB after any healthcare service that was billed to your insurance: doctor visits, lab tests, hospital stays, prescriptions (if you have prescription coverage), and more.
The key sections of an EOB
Service information
This section lists the date of service, the name of the provider, and a description of the service — usually a medical billing code rather than plain English. Common codes include CPT codes (procedure codes) and ICD codes (diagnosis codes).
Amount billed
This is what the provider originally charged. It's almost never what anyone actually pays — providers bill at a "list price" that insurance companies negotiate down significantly.
Discount or adjustment
If your provider is in-network, your insurer has a negotiated rate with them. The "discount" line shows how much was knocked off the billed amount. This is one of the main financial benefits of using in-network providers.
Amount the plan paid
After the discount is applied, this is what your insurance company actually paid the provider.
Your responsibility
This is what you owe. It may include your deductible (if you haven't met it yet), your copay, your coinsurance, or costs for services your plan doesn't cover.
Not covered
If a service was denied or not covered, this column will show a reason code. Reason codes are explained in a key elsewhere on the EOB — always look these up if you see an amount in this column.
EOB vs. bill: which one is right?
If the amount on your provider's bill doesn't match the "your responsibility" figure on your EOB, don't just pay the bill. Call your provider's billing department and ask them to reconcile the two. Billing errors are common, and you should only pay what your EOB says you owe.
What to do if something looks wrong
- Check the service date and provider name — make sure it matches what you actually received.
- Look up any reason codes — the EOB will have a key. If a claim was denied, the reason code tells you why.
- Compare against your plan's Summary of Benefits — this document explains what your plan covers and at what cost-sharing level.
- Call your insurer — the member services number is on the back of your insurance card and at the top of your EOB.
- File an appeal if a claim was wrongly denied — you have the right to appeal. See our guide on how to appeal a denied insurance claim.
Keep your EOBs
Hold onto EOBs for at least one year, or until you've confirmed that all bills for that service have been paid and resolved. They're useful evidence if billing disputes arise later.
Sources: Centers for Medicare & Medicaid Services (CMS), Healthcare.gov — Explanation of Benefits
