How to Read Your Explanation of Benefits (EOB) — Line by Line

Every time your insurance processes a medical claim, they send you an Explanation of Benefits (EOB). Most Americans throw it away assuming it’s junk mail. That is a mistake. 31% of patients who compare their EOB to their provider bill find a discrepancy — and the EOB is the document that proves what you actually owe. Here is how to read it, line by line.

1. What an EOB is (and is not)

An Explanation of Benefits (EOB) is a document your insurance company sends after a medical claim is processed. It explains:

• What service was provided and by whom
• What the provider charged (billed amount)
• What your insurance agreed to pay (allowed amount)
• What your insurance actually paid
• What you owe (patient responsibility)

An EOB is not a bill. You should not send a payment in response to an EOB. Wait for the provider’s bill, then compare it to your EOB. The provider’s bill should ask for the exact “patient responsibility” amount shown on your EOB — not more.

EOB vs. Remittance Advice (RA): When the insurer pays the provider, the provider also receives a document called a Remittance Advice (RA). The RA is the provider’s version of the EOB — it tells the billing department exactly what insurance paid and what the patient owes. When the EOB and the provider’s bill disagree, it often means the billing department didn’t correctly apply the RA before sending your bill.

2. The key columns explained

EOBs vary by insurer, but every EOB contains the same core information, usually in a table with these columns:

3. The contractual adjustment: why billed ≠ what you owe

The most confusing part of any EOB is the gap between the billed amount and the allowed amount. In the example above, the provider billed $850 but the allowed amount is only $310. Why?

When a provider joins an insurance network, they sign a contract agreeing to accept a negotiated rate for each service. That rate is the allowed amount. The difference between what they billed ($850) and what they’re actually paid ($310 total from insurance + patient) is the contractual adjustment — the provider writes it off. They cannot collect it from you.

This is why in-network care is cheaper. An out-of-network provider has no such contract. They can bill $850 and pursue the full amount. Your insurance might pay a portion (if you have out-of-network coverage), and the provider can balance bill you for the rest.

4. What “paid,” “denied,” and “in process” mean

Each claim on an EOB has a status. Common statuses and what to do about them:

5. How to spot billing errors on your EOB

Your EOB is your primary tool for catching billing errors. Here is what to look for:

1. Services you did not receive. Check the service date, procedure code, and provider. If you see a charge for a service you didn’t have, that is a potential duplicate or phantom charge. Call your provider’s billing department immediately.
2. Wrong date of service. A date that doesn’t match your records could indicate your claim was mixed up with another patient’s.
3. Wrong provider name. If the provider listed isn’t who you saw, a claim may have been filed under the wrong provider number — especially common with group practices.
4. Upcoded procedures. The procedure code determines what you’re charged. An office visit coded as a 99214 (detailed exam) instead of a 99213 (standard exam) can cost you significantly more in deductible or coinsurance. If the complexity of the visit code seems higher than what occurred, ask your provider for the medical record that justifies it.
5. Unbundled procedures. Some procedures have global codes that cover the whole service. When a provider separately bills for components that should be bundled into the global code, you’re overcharged. This shows up as multiple procedure codes for what should have been one charge.
6. Denied preventive care. ACA-required preventive services (annual physicals, mammograms, colonoscopies) must be covered at $0 cost-sharing when billed correctly. If your EOB shows cost-sharing for a service that was supposed to be preventive, the provider may have used the wrong billing code.

6. Comparing your EOB to your provider bill

When you receive a bill from your provider, follow these steps:

1. Match the date of service. Find the corresponding EOB for the same date and provider. Your insurer’s member portal lets you filter by date.
2. Compare the “patient responsibility” on the EOB to the “amount due” on the bill. They should be identical. If the bill is higher, that is a discrepancy.
3. Check that the allowed amount was applied. The provider should not be billing you the full billed amount. If their bill shows a number close to the billed amount (not the allowed amount), they may not have applied the insurance payment yet — or it’s an error.
4. Confirm payment credit. The bill should show the insurance payment as a credit. If it doesn’t show the insurance payment at all, the billing department may not have processed the EOB yet. Call before paying.
5. Do not pay a bill that exceeds your EOB’s patient responsibility until you have spoken with both the provider’s billing department and your insurer to resolve the discrepancy.

7. Keeping EOBs for taxes and records

EOBs are important financial records. Here is how to manage them:

• Keep EOBs for at least three years in case of IRS audit. If you claim medical expense deductions (itemized deductions exceeding 7.5% of AGI), your EOBs are the supporting documentation.
• Keep indefinitely for major procedures. If you had surgery, a hospitalization, or treatment for a serious condition, keep those EOBs permanently. Billing disputes and insurance appeals can resurface years later.
• Download PDFs from your member portal. Most insurers archive EOBs for 2–3 years online. Download and save copies yourself — don’t rely on the insurer’s portal being accessible indefinitely.
• Prescription EOBs are separate. If your pharmacy benefits are managed by a separate PBM (Pharmacy Benefit Manager), your drug EOBs come from a different source. Check your insurer’s member portal or the PBM portal separately.

Frequently asked questions

Sources

• HealthCare.gov: Explanation of Benefits
• Centers for Medicare & Medicaid Services: Reading Your Medicare Summary Notice
• Consumer Financial Protection Bureau: Medical Billing Errors Report (2025)
• American Medical Association: CPT Code Guidelines
• Kaiser Family Foundation: Understanding Your Health Insurance EOB