It is not a bill, it is the scorecard
The explanation of benefits is your insurer's accounting of one claim: what the provider charged, what the contract allows, what the plan paid, and what it says is yours. Providers sometimes bill from the wrong column of that scorecard. Reading the EOB is how you catch it, and the whole document turns on five numbers.
Billed amount and allowed amount
The billed amount is the provider's list price, and almost nobody pays it. The allowed amount is the rate your plan negotiated for that service. If a provider bills you the difference on an in network claim, that is balance billing, and on many emergency and hospital based claims federal law now prohibits it.
Plan paid and patient responsibility
Plan paid is what the insurer actually sent. Patient responsibility is the only number that should ever reach your wallet: your deductible, copay, and coinsurance for that claim, added up. When the provider bill and the patient responsibility disagree, the EOB wins the argument, and the fix is a corrected bill, not a payment.
Deductible and out of pocket credits
The EOB also records how much of the claim counted toward your deductible and out of pocket maximum. Those credits matter later in the year: once the out of pocket maximum is met, covered in network care is paid in full, and bills that arrive after that point deserve a second look before paying.
Remark and denial codes
The small codes at the bottom explain every reduction. A denial code turns the EOB into an action item: not medically necessary, no authorization, coding error, or timely filing are each fixed a different way, and each carries its own appeal deadline. The remark text, not the total, tells you which fight you are in.
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Open the free checkerCommon questions
Why did I get an EOB instead of a bill?
The EOB comes from your insurer and explains how a claim was processed. The bill comes from the provider. You need both: the EOB says what you owe, the bill says what they are asking, and fighting a medical bill starts with comparing the two.
The provider bill is higher than my EOB. Who is right?
For an in network claim, the EOB patient responsibility is the number that counts. Send the provider a copy of the EOB and ask for a corrected bill in writing. Do not pay the higher figure while the correction is pending.