How to read a medical bill (and check it against your EOB)

When a medical bill arrives, it can look like a wall of codes and numbers. You don't need to be a billing expert to make sense of it. You need to know where to look, and you need 1 other document: your explanation of benefits (EOB).

This guide shows you how to read a medical bill, piece by piece. It explains the parts of your EOB, what billing codes mean, and why 1 visit can bring several bills. Then it shows you how to check the bill before you pay.

Which problem do you have?

Start with the problem that sounds most like yours. Each guide explains what's going on and what to do next.

What are the parts of a medical bill?

Bills from hospitals and doctors' offices look different, but most have the same basic parts. Here's what to find, from top to bottom.

• Provider and account details. The name of the hospital or practice, a phone number for billing questions, and your account number. Use the account number every time you call or write.
• Patient name. Check that it's you, or the person whose bills you handle. A bill for someone else's care is an easy mistake to miss.
• Date of service. The day you got care. For a hospital stay, it may be a range of dates.
• Statement date. The day the bill was printed. It's not the date of your care.
• Charges. What the provider billed, either line by line or as 1 total.
• Adjustments. Amounts taken off the charges. The biggest one is usually your insurer's network discount. Bills often call it an "insurance adjustment" or "contractual adjustment."
• Payments. What your insurer paid, plus anything you paid, like a copay at the front desk.
• Amount due. What the provider says you owe now. It should equal the charges minus the adjustments and payments.
• Due date. When the provider wants to be paid. If you're questioning the bill, call before this date and ask them to hold your account.

A bill may also say "insurance pending." That usually means the provider sent a claim and is still waiting for your insurer to process it.

Say Maya's son gets an X-ray and a cast for a broken wrist at an in-network hospital on July 9, 2026. A few weeks later, this summary bill arrives.

Line on the bill	What it says	What it means
Account number	00458812	Use it every time you call or write.
Statement date	August 4, 2026	When the bill was printed.
Date of service	July 9, 2026	When the care happened. Match it to the EOB.
Total charges	$3,200	The hospital's full price, before any discount.
Insurance payment	−$1,120	What Maya's plan paid the hospital.
Insurance adjustment	−$1,680	The plan's network discount.
Patient payment	−$100	The copay Maya paid at check-in.
Amount due	$300	What the hospital says Maya owes now.
Due date	September 3, 2026	When the hospital wants to be paid.

The math works: $3,200 − $1,120 − $1,680 − $100 = $300.

Next, Maya finds her EOB for July 9. It shows provider charges of $3,200, allowed charges of $1,520, $1,120 paid by her insurer, and $400 under "What You Owe."

The $300 due plus the $100 she already paid equals $400. The bill matches the EOB, so she pays it.

Summary bill vs. itemized bill: what's the difference?

A summary bill shows totals. It may group charges into a few lines, like "radiology" or "pharmacy," with 1 amount each. It tells you what the provider wants, but not what you were charged for.

An itemized bill lists every charge, 1 line at a time. Each line usually shows the date, a description, a billing code, the quantity, and the price. That's where you can spot a duplicate charge, a service you didn't get, or a quantity that looks wrong.

You can ask any hospital or doctor's office for an itemized bill. Our guide on how to get an itemized bill includes a phone script, and our itemized bill request letter puts the request in writing. If you have Medicare, your Medicare Summary Notice says you can ask the facility for an itemized statement for any claim.

What are the parts of an explanation of benefits?

Your EOB comes from your insurer after it processes a claim. It shows what the provider charged, what your plan paid, and what you may owe.

An EOB is not a bill. You may get it by mail, or you may find it in your insurer's app or website.

The Centers for Medicare & Medicaid Services (CMS) publishes a sample EOB that labels each part. Your insurer may use different words, but the parts are usually the same.

The most important line is What You Owe. For covered care from a network provider, the bill usually shouldn't ask for more than this amount.

That's because network providers agree not to bill you for the difference between their charge and your plan's allowed amount. If you paid something at the visit, subtract it from What You Owe before you compare.

If an EOB says a claim was denied, look at the remark or reason code. It tells you why.

Some denials are simple paperwork problems that the provider can fix. Others need an appeal. Our guide to denial codes on your EOB explains the common ones.

What is a CPT code, and do you need to know them?

Short answer: no. Billing codes are how providers tell your insurer what they did and why. You don't need to memorize them. But knowing the main types helps you ask better questions.

• CPT codes describe medical services and procedures, like an office visit, an X-ray, or a surgery. Each one is 5 digits long. The American Medical Association maintains them. CMS calls them HCPCS Level I codes.
• HCPCS Level II codes cover products, supplies, and services that CPT codes don't, like ambulance rides and medical equipment. Each one is a letter followed by 4 numbers. CMS maintains them.
• Diagnosis codes come from a list called ICD-10-CM. They describe the reason for your care, like a condition, a symptom, or an injury.
• Revenue codes show up on hospital bills. They group charges by type, like rooms, lab tests, or radiology. For example, revenue codes that start with 030 are lab tests, and codes that start with 032 are radiology.
• Modifiers are short add-ons to a procedure code, like 25, 59, RT, or LT. They add detail. RT and LT, for example, show whether a procedure was on the right or left side of the body.

Codes are most useful as a way to ask questions. When a line doesn't make sense, write down the code and ask the billing office what it is and why it was billed.

Check that each code matches care you remember. Check that the quantity makes sense, too.

A code listed twice on the same day, or a code for a bigger visit than the one you had, is worth asking about. Our list of common medical billing errors shows what else to look for.

How to read a hospital bill

A hospital bill has the same parts as any other bill, but it's often much longer. An itemized hospital bill can run several pages, with charges grouped by department. Take it 1 page at a time.

• Match every date of service to a day you were actually there.
• Check room charges against the length of your stay.
• Look at quantities. A line for 10 of something when you got 1 is worth a question.
• Look for the same item listed twice on the same day. Our guide to duplicate charges on a medical bill shows how to spot and remove one.
• Circle any drug, supply, or test you don't recognize, and ask what it was.

You don't have to settle every question in 1 call. Write down what you asked, who you spoke with, and what they said. Then follow up on anything they couldn't answer.

Why does 1 visit create several bills?

A hospital visit often leads to 2 kinds of bills. The hospital sends a facility bill for its part of your care. That covers things like the room, nursing care, supplies, and equipment.

Each doctor or other professional who cared for you may send a separate bill for their services.

That's why an emergency room visit can bring 3 or 4 bills. You might get 1 each from the hospital, the emergency doctor, the radiologist who read your scan, and a lab.

Medicare works the same way. With Original Medicare, you pay the hospital a copayment for the emergency visit and for each hospital service. After your Part B deductible, you also pay 20% of the Medicare-approved amount for the doctor's services.

Each bill should have its own EOB, so match them 1 at a time. If you can't find an EOB for a bill, the provider may not have sent a claim to your insurer yet.

Some hospital-owned clinics also add a facility fee to a regular office visit. Our guide to the facility fee on a medical bill explains when that happens and when to question it.

If a doctor who treated you at an in-network hospital was out of network, federal rules may protect you. See does the No Surprises Act apply to my bill.

For big events, it helps to know which bills to expect. Our guides to emergency room bills, bills after surgery, and hospital bills after having a baby map out the bills you're likely to get.

Why are hospital bills so high?

The first number on a hospital bill is usually the hospital's list price. Hospitals keep a master list of prices, called a chargemaster. Federal rules define the "gross charge" as the price on that list, before any discounts.

Insurers negotiate their own rates with the hospitals in their networks. Hospitals also set a discounted cash price for people who pay on their own.

Since January 1, 2021, hospitals have had to post their prices online. Our guide to hospital price transparency lookup shows how to find them.

If you have insurance, the number that matters is the allowed amount on your EOB, not the list price. Your coinsurance is figured as a percent of the allowed amount.

If you don't have insurance, ask for the discounted cash price or a self-pay discount on a medical bill. Also ask whether you qualify for hospital charity care.

What if the hospital bill comes before insurance is processed?

Sometimes a bill arrives before your insurer has finished the claim. It may show the full charges, with no insurance payment or discount. If you pay it now, you may pay more than you owe and then wait for a refund.

Here's what to do instead:

1. Look for the claim in your insurer's app or website. It may show up there before the EOB comes in the mail.
2. Call the billing office. Confirm they have your current insurance, and ask whether and when they sent the claim.
3. If they didn't send it, ask them to bill your insurer first. Our bill insurance first letter puts that request in writing.
4. Ask them to hold your account while the claim is processed, so it doesn't go to collections.
5. When the EOB arrives, compare it with the new bill before you pay.

If you have Original Medicare, the law requires your doctor, provider, or supplier to file Medicare claims for covered services. You can usually see a claim in your Medicare.gov account within 24 hours after Medicare processes it.

What if a bill shows up months later?

A bill can arrive long after your care, especially if a claim was delayed, sent to the wrong plan, or denied. Providers usually have a deadline to send claims to your insurer. For Original Medicare, claims must be filed within 12 months of the date of service, with a few exceptions.

Our guide on how long a hospital has to bill you explains what a late bill can mean. It also covers what to ask before you pay.

How to check your bill against your EOB

Once you have both documents for the same visit, compare 4 numbers.

If all 4 match, the bill is likely right. If they don't, the gap usually points to the problem. A missing discount, a payment that wasn't posted, and a duplicate line are common causes.

Our step-by-step guide to EOB vs. medical bill walks through each check with an example. If your bill asks for more, see why your medical bill is higher than your EOB. You can also enter your numbers in our bill and EOB checker, or print our medical bill checklist to use before you pay.

What people with Medicare get instead of an EOB

If you have Original Medicare, you get a Medicare Summary Notice (MSN) instead of an EOB. Like an EOB, it's not a bill. It lists the services billed to Medicare, what Medicare paid, and the most a provider can bill you.

Medicare mails an MSN every 6 months if you had any services or supplies in that time. You can sign up for electronic MSNs instead. Then you get an email for any month with a processed claim.

On a Part B notice, the key columns are "Amount Provider Charged," "Medicare-Approved Amount," "Amount Medicare Paid," and "Maximum You May Be Billed."

Compare that last column with your bill. The last page explains how to appeal. Medicare must receive your appeal within 120 days from the date you get the notice.

If you have a Medicare Advantage plan, you get an EOB from your plan instead. It comes each month you use your benefits. Our guide on how to read a Medicare Summary Notice walks through it column by column.

Reading bills for someone else

If you're helping a parent, partner, or child with medical bills, the same checks apply. What changes is getting permission to ask questions.

Under federal privacy rules, providers and health plans may talk with a family member who helps with a patient's care or pays their bills. The patient has the right to object. Providers aren't required to share, though, so a signed permission form on file with each provider can make calls easier.

Medicare has its own rule. Before 1-800-MEDICARE can share someone's information with you, the person with Medicare needs to give written permission. The form is called an "Authorization to Disclose Personal Health Information."

Keep a folder for each visit, with the bill, the EOB or MSN, and notes from every call. Our guide to help with an elderly parent's medical bills covers permissions, Medicare, and financial help step by step.

When to get help

You can often sort out a confusing bill yourself with 1 or 2 calls. It's worth getting help when:

• The billing office can't explain a charge, or the numbers still don't match after you call.
• Your insurer denied the claim and you don't understand why.
• You think you got a surprise out-of-network bill.
• The bill is already in collections, or you're getting collection calls. See our guide to a medical bill in collections.
• You're handling bills for someone else and you're short on time.

Your insurer's member services team can explain your EOB. The number is on your insurance card.

If your insurer isn't helping, contact your state insurance department or consumer assistance program. For surprise out-of-network bills, call the No Surprises Help Desk at 1-800-985-3059.

If you have Medicare, call 1-800-MEDICARE (1-800-633-4227). Your State Health Insurance Assistance Program (SHIP) also offers free, local counseling.

A nonprofit such as Patient Advocate Foundation may be able to help with billing and insurance problems. A medical bill advocate can take on the calls for you. If a provider sues you, talk with an attorney or your local legal aid office.

If your bill is right but you can't afford it, you still have options. You may be able to negotiate a hospital bill, set up a payment plan, or apply for financial help.