How to Read an Explanation of Benefits (EOB)

Your EOB Is Not a Bill

An Explanation of Benefits (EOB) arrives after your insurance processes a claim. It’s confusing, it’s jargon-heavy, and many people throw it away. Don’t. Your EOB is the single most important document for understanding what happened with your healthcare costs — and it’s where billing errors hide.

Let’s decode it section by section.

The Key Sections of Every EOB

1. Service Information

This section lists:

• Date of service — when you received care
• Provider name — who provided the care
• Procedure code (CPT) — what was done
• Description — plain-language name of the service

Check that these match your actual experience. Wrong dates, wrong providers, or procedures you don’t recognize are red flags for billing errors or even fraud.

2. Amount Billed

This is what the provider charged — their “list price.” This number is often shockingly high and bears little relationship to what anyone actually pays. Don’t panic when you see it.

3. Allowed Amount (or “Negotiated Rate”)

This is what your insurance company has agreed to pay for this service based on their contract with the provider. It’s typically 40-70% less than the billed amount. This is the number that matters — it’s what the math is based on.

4. Insurance Paid

How much your insurance company actually paid the provider. This is the allowed amount minus your cost-sharing (deductible, copay, coinsurance).

5. Your Responsibility

What you owe. This is broken into components:

• Deductible: Amount applied to your annual deductible (you haven’t met it yet for this portion)
• Copay: Fixed dollar amount for this type of service
• Coinsurance: Your percentage of the allowed amount (typically 20%)
• Not covered: Services your plan doesn’t cover at all

6. Adjustments/Write-offs

The difference between what the provider billed and the allowed amount. In-network providers must accept this write-off — they cannot bill you for it. This is called “balance billing” and it’s prohibited for in-network providers.

Common EOB Errors to Watch For

Coding Errors

• Wrong CPT code: A more expensive procedure code than what was actually performed
• Upcoding: Billing for a complex visit (99215) when you had a simple one (99213)
• Unbundling: Billing separately for services that should be one bundled code

Coverage Errors

• Preventive service denied: Screening colonoscopies, mammograms, and vaccinations should be covered at 100% under ACA
• Wrong network tier applied: Provider listed as out-of-network when they should be in-network
• Deductible not credited: Previous payments not reflected in your deductible balance

Duplicate Charges

• Same service on the same date billed twice
• Two claims for the same procedure from different billing entities (if not appropriate component billing)

What to Do If You Spot an Error

1. Compare the EOB to your actual experience. Did you receive these services? On these dates? From these providers?
2. Call your insurance company (number on the EOB). Ask them to explain anything that doesn’t make sense.
3. Call the provider’s billing department if you believe the procedure was coded incorrectly.
4. File an appeal if a service was incorrectly denied. You have the right to appeal, and many initial denials are overturned.
5. Keep records of every call — date, representative name, reference number, what was discussed.

EOB vs. Bill: Know the Difference

Your EOB tells you what you’ll owe. The actual bill from the provider is what triggers payment. Don’t pay a provider bill until you’ve received and reviewed the EOB from your insurance. If the amounts don’t match, something is wrong.

• If the bill is higher than your EOB “patient responsibility”: The provider is overcharging you. Call them with your EOB in hand.
• If you get a bill before an EOB: The claim may not have been submitted to insurance. Call the provider to confirm they billed your insurance.

The Bottom Line

Read every EOB. Compare it to your bills. Check that services match what you received. Verify the math. It takes 5 minutes per EOB and can save you hundreds or thousands of dollars in billing errors.

Related Reading

• FAQ — More about understanding healthcare costs
• Compare Prices — See what procedures should cost before you receive care