How to Read an Explanation of Benefits (EOB)
Last updated: 2026-03-25
By the Medical Bill Reader Team — About the author
Important Disclaimer
This tool provides general explanations of medical billing codes and charges for informational purposes only. It does not constitute financial or medical advice. Always verify charges directly with your healthcare provider and insurance company before taking action.
What Is an Explanation of Benefits?
An Explanation of Benefits (EOB) is a statement from your insurance company that breaks down how a medical claim was processed. It is not a bill — it is a summary of what the provider charged, what insurance covered, and what you may owe. You typically receive an EOB after every medical visit or procedure. Reading your EOB carefully is the single most effective way to catch billing errors before you pay an incorrect amount.
Key Sections of an EOB
Every EOB includes: the patient name and claim number, the provider name and date of service, the billed amount (what the provider charged), the allowed amount (what insurance agreed to pay for that service), the insurance payment (what your plan actually paid), and your responsibility (copay, coinsurance, or deductible). Some EOBs also include a reason code explaining why a charge was denied or adjusted.
Billed Amount vs. Allowed Amount
The billed amount is the provider's list price. The allowed amount is the maximum your insurance will pay for that service based on its contract with the provider. The difference between these two amounts is the contractual adjustment — in-network providers agree to write off this difference. You should never owe the difference between the billed and allowed amounts for in-network services.
Understanding Denials and Reason Codes
If a claim is denied, the EOB will include a reason code or explanation. Common denial reasons include: prior authorization not obtained, service not covered under your plan, out-of-network provider, timely filing limit exceeded, and coding errors. If your claim was denied, you have the right to appeal. Most denied claims that are appealed are eventually paid — studies show that roughly 50-60% of appealed claims are overturned.
How to Compare Your EOB to Your Bill
When you receive a medical bill, pull up the corresponding EOB and compare them line by line. The patient responsibility on the EOB should match the amount on your bill. If the bill is higher than what the EOB says you owe, contact the billing department — the provider may not have applied your insurance payment correctly, or may be balance billing you improperly.
Frequently Asked Questions
Is an EOB the same as a medical bill?
No. An EOB is an informational statement from your insurance company showing how a claim was processed. A medical bill is a payment request from your healthcare provider. Always compare the two before paying.
What should I do if my EOB says I owe nothing but I got a bill?
Contact the provider's billing department and share your EOB. The provider may not have received insurance payment yet, or there may be a processing error. Do not pay until the discrepancy is resolved.