Medical bill vs EOB: how to compare them

If you have insurance, you get two documents for the same visit, and they are easy to confuse. Comparing them is one of the most useful things you can do before paying anything.

They come from different places

The bill comes from the provider. It asks you for money.

The Explanation of Benefits comes from your insurer. It explains what the provider charged, what the insurer allowed, what the insurer paid, and what it calculated you may owe. It is not a request for payment, and most EOBs say so directly.

The numbers that should line up

Line the two documents up side by side and compare these:

On the EOB	On the bill	What it should look like
Amount billed	Total charges	Usually identical for the same claim.
Allowed amount	Often not shown	The maximum your insurer considers payable.
Plan paid / insurance payment	Insurance payments	Should match.
Discount / plan adjustment	Adjustments	Should match.
Deductible + coinsurance + copay	Patient responsibility	The EOB's cost-sharing total should equal what the bill asks you to pay, plus any non-covered service.
Patient responsibility	Patient responsibility	The number to compare most carefully.

When patient responsibility differs

This is the difference that matters most, and there are ordinary explanations for it:

• The bill was sent before the claim finished processing. The provider billed you at list price, then the insurer processed the claim afterwards.
• The claim was reprocessed. Insurers sometimes reprocess a claim and issue a corrected EOB. The provider may be working from the older one.
• A service was never submitted to insurance. Then there is no EOB line for it at all.
• The documents cover different visits. Check the dates of service and the claim number before comparing anything.
• Something was not covered. Non-covered services show on the bill but may not appear as cost-sharing on the EOB.

None of these mean anyone did anything wrong. All of them are worth a phone call before you pay, because in several of them the amount you owe changes.

How to ask

Call the provider's billing department first, with the EOB in front of you:

"My Explanation of Benefits from [insurer] for the [date] visit shows patient responsibility of $X, but my statement asks for $Y. Can you help me understand the difference? Has the claim been fully processed?"

If the provider says the amount is correct and the insurer's EOB says otherwise, call the insurer next and ask them to explain how they processed the claim.

Getting it done faster

You can open both documents in MedBillCheckup; they are read on your device and never uploaded. We will pull the amounts out of each, compare them field by field, and tell you exactly which ones differ and by how much, along with the questions to ask each side. We never tell you which document is correct, because that is not something a document comparison can establish.