Understanding Your Explanation of Benefits

An Explanation of Benefits (EOB) is the statement your insurance company sends after a claim. It is not a bill. It shows what the provider charged, what your plan paid, the adjustments, and the amount you owe. If an in-network provider's bill is higher than the EOB's patient-responsibility figure, something is wrong.

After you receive medical care, your insurance company sends you an Explanation of Benefits — an EOB. It's not a bill. But it's one of the most important documents in your billing journey, and it's tempting to throw it away without reading it.

That's a mistake.

Your EOB tells you exactly what was billed, what your insurance paid, what adjustments were made, and what you owe. It's your best tool for catching errors before you pay a single dollar.

What's on an EOB

Every EOB includes:

• Patient name and date of service — who was treated and when
• Provider name — the doctor, hospital, or lab that billed
• Service description and codes — what procedure or visit was billed
• Amount billed — what the provider charged
• Insurance adjustment — the negotiated discount your insurance secured
• Amount paid by insurance — what your plan covered
• Your responsibility — what you owe (copay, coinsurance, deductible)
• Denial reason (if applicable) — why a charge wasn't covered

How to Read It

Start With the Total

Look at "Amount You Owe" or "Patient Responsibility." This is what the provider should be billing you — no more.

Compare Against Your Bill

If an in-network provider's bill is higher than the "Patient Responsibility" on your EOB, something is wrong. (Out-of-network is different — see balance billing.) Common causes:

• The provider is billing you for the full charge instead of the adjusted amount
• A charge was denied and the provider is balance-billing you (which may be illegal)
• The provider hasn't applied your insurance payment yet

Check for Denied Services

Look for any line items marked "denied" or "not covered." Read the denial reason. Common reasons include:

• Prior authorization not obtained — the provider didn't get pre-approval
• Out-of-network — the provider isn't in your plan's network
• Not medically necessary — the insurer disagrees with the treatment
• Coding error — the wrong code was submitted

Many denials are fixable. A coding error can be corrected by the provider. A medical necessity denial can be appealed with documentation from your doctor.

Verify the Services

Make sure every service listed on the EOB actually happened. If there's a charge for a procedure you never received, that's a billing error — and it can cost you twice: once on that line, and again later, because the phantom charge counts against your deductible and your plan's visit or frequency limits, so legitimate care down the road costs you more or gets denied.

What to Do When You Find a Problem

1. If the bill is higher than the EOB's patient-responsibility figure, the dispute names the line, cites that figure, and asks for a corrected statement. BillFighter's Dispute Letter does exactly this, and asks that the account stay out of collections while it is reviewed. You read it, sign it, and mail it yourself, or have BillFighter send it by certified mail with the delivery record on file. A letter creates a dated record; a phone call doesn't.
2. If an entry makes no sense, you can ask your insurer, in writing, to explain it. Upload the EOB first: the free scan reads it and tells you, in plain words, which lines look wrong and why. Check my bill, free →
3. If the provider doesn't correct it, keep every reply. If the biller pushes back, BillFighter's Follow-Up Letter refers to the first letter and the date it was sent.
4. If a denial is wrong, appeal it. BillFighter's Insurance Appeal letter answers the denial reason on the EOB. If the internal appeal fails, you can usually request an independent external review, whose decision binds the insurer. If the insurer ignores the appeal, the Insurance Commissioner Complaint puts your state regulator on it.

Calling the provider is optional. It can help for one thing: confirming the address to send your letter to. Ask them to put anything they tell you in writing, and note the date, the time, and the name.

What BillFighter does here

Upload your EOB or the bill. BillFighter reads what you upload and flags the lines that look wrong — a denied line, a charge above the patient-responsibility figure, a code the bill itself doesn't support. Then it drafts, in your name, the letter that fits: a dispute to the provider, or an appeal to the insurer. You read it, sign it, and send it: mail it yourself, or have BillFighter send it by certified mail.

BillFighter reads your documents, prepares the letters that fit, and keeps the case organized. With the Fight Kit, you print and mail the letters. With In Your Corner, BillFighter mails up to two of your approved letters by certified mail and tracks delivery. You review every draft. BillFighter does not call or negotiate with the other side, and it is not a law firm.

Don't throw away your EOB. Use it. Check my bill, free →

See a sample letter: Insurance appeal letter sample →