By Qamar S, 15 years in US medical billing ยท Last reviewed September 24, 2026
An Explanation of Benefits (EOB) is a statement from your health insurer that shows what a provider charged, what the insurer paid and what you may owe. It is not a bill. Wait for the EOB before paying any medical bill, then check that the provider’s bill matches the “patient responsibility” amount on the EOB.
Rule of thumb: EOB = your insurer’s receipt. Bill = the provider asking for money. The amount you owe on the bill should match “What you owe” (or “Patient responsibility”) on the EOB. If the bill is higher, ask why before paying.
The parts of an EOB, explained
| EOB line | What it means |
|---|---|
| Provider / Date of service | Who treated you and when. Check that you actually had this visit. |
| Service description or code | What was done, often shown as a CPT code (for example, 99213 for an office visit). |
| Amount billed (Charges) | The provider’s full price. You almost never owe this full amount if you’re in network. |
| Allowed amount | The price your insurer agreed to pay in-network providers. |
| Discount / Adjustment | The difference between the billed and allowed amounts. In network, the provider writes this off. |
| Plan paid | What your insurer paid the provider. |
| Deductible / Copay / Coinsurance | The part of the allowed amount that is your share. |
| What you owe (Patient responsibility) | The maximum you should pay the provider for this service. |
| Remark or reason codes | Short codes explaining denials or adjustments. The key is usually on the back or last page. |
A simple example
You see an in-network specialist. The EOB shows:
- Amount billed: $300
- Allowed amount: $180 (so $120 is a network discount you don’t pay)
- Your deductible is already met, and your coinsurance is 20%
- Plan paid: $144
- What you owe: $36
If the specialist’s office later sends a bill for $156 or $300, something is wrong. In network, they generally cannot bill you for the $120 discount.
How to compare your EOB with your bill
- Match the date of service and provider on both documents.
- Compare “What you owe” on the EOB with the balance on the bill.
- Look for denied lines. A denial reason code can mean a coding error, a missing referral or missing information, which can often be fixed.
- Check for duplicates. The same service billed twice on the same day is a common error.
- Ask for an itemized bill if the provider’s bill only shows a total.
From the billing side: most “wrong” patient bills I’ve seen weren’t fraud. They were timing problems. The provider billed you before the insurer finished processing, or the insurer paid later and the office didn’t update your balance. Before paying, call the billing office and ask: “Has my insurance payment from [date] been posted to this account?”
Common EOB reason codes (and what to do)
- Not covered / not medically necessary: ask the provider if the diagnosis code was correct, then consider an appeal.
- Out of network: check whether the No Surprises Act applies. See our No Surprises Act guide.
- Missing information or referral: the provider can often correct and resubmit the claim.
- Coordination of benefits: your insurer needs to know whether you have other coverage. Answering their questionnaire usually fixes it.
Frequently asked questions
Is an EOB a bill?
No. It’s a summary from your insurer. Pay only the bill from your provider, and only after checking it against the EOB.
Where do I find my EOBs?
Most insurers post them in your online member account and app. You can also request paper copies.
What if my EOB shows a service I didn’t receive?
Call your insurer right away. It could be a billing error or, rarely, medical identity theft.
What if I disagree with a denial on my EOB?
You have the right to appeal. See how to dispute a medical bill.
Sources
*This guide is educational and is not legal or insurance advice. See our Disclaimer.*