Reading an Explanation of Benefits: What Each Line Means

What an Explanation of Benefits shows, how to match it to a provider's bill, what partial denials mean, and how to spot medical identity theft.

iHealthBenefit · Last reviewed October 26, 2026 · 6 min read

A few weeks after a doctor visit, a statement from your health plan shows up in the mail or your online account. It is full of numbers, and some of them are large. Before you reach for your wallet, look at the top: it is probably an Explanation of Benefits, or EOB.

CMS's consumer guide Roadmap to Getting Health Care (September 2026) puts it plainly: an EOB is not a bill. It shows what was billed, what your plan covered and what you may need to pay. If you owe money, the bill comes separately from your provider.

This guide explains what an EOB contains, how to match it against a provider's bill, what to do when something looks wrong, and how EOBs help you spot medical identity theft. It is general information, not insurance, legal or medical advice.

What an EOB is and when you get one

After each visit to a provider or health care service, your plan sends an EOB, according to CMS. The Federal Trade Commission's guide to medical identity theft (September 2024) describes what it tells you: the doctor you visited, the date of your visit, the services the doctor provided, the cost of those services, how much your health insurance covered and how much you'll have to pay.

Each EOB relates to a claim, which HealthCare.gov defines as a request for payment that you or your health care provider submits to your insurer when you get items or services you think are covered. If you prefer less paper, the FTC suggests getting EOBs and medical bills online, which also limits how much medical information arrives in your mailbox.

The parts of a typical EOB

Layouts and labels vary from plan to plan, but you will usually find versions of these items:

Patient and provider. Who got care and who provided it. On a family plan, each person's claims are listed by name.
Claim number and date of service. Use these whenever you call the plan about this visit.
Services. A short description of each service, sometimes with billing codes.
Amount billed. What the provider charged the plan.
Allowed amount. The maximum the plan will pay for a covered service, sometimes called the negotiated rate. For in-network care, the difference between the billed and allowed amounts is usually a discount you don't owe.
Plan paid. What the insurer paid the provider.
Your share. The amount applied to your deductible, plus any copayment or coinsurance, and anything the plan didn't cover.
Remarks or codes. Notes or codes explaining adjustments or denials, along with what they mean.
Running totals. Some EOBs also show how much you have paid toward your deductible and out-of-pocket maximum so far this year.

A hypothetical example shows how the numbers relate. Say a lab bills $300, the plan's allowed amount is $120, you haven't met your deductible, and the plan paid $0. Your share would be $120, applied to your deductible, and the remaining $180 would be a network discount, not something you owe. The lab's bill to you should match the $120.

Matching your EOB to the provider's bill

The most useful habit is to wait for the EOB before paying a large medical bill, then compare the two. Look for:

The same patient, provider, date of service and services on both documents.
A bill that matches the "your share" or "you may owe" amount on the EOB.
Services you didn't receive, or duplicates of the same service.

If the provider's bill is higher than what the EOB says you owe for in-network care, ask why. HealthCare.gov's glossary notes that a preferred (in-network) provider may not balance bill you for covered services, meaning they can't charge you the difference between their price and the allowed amount. CMS advises that if you think you were charged for services your plan should pay for, you keep the bill and call your health plan right away.

When a claim is partly or fully denied

Sometimes the EOB shows that the plan paid nothing or less than you expected. Under federal rules for job-based plans, the Department of Labor's guide Filing a Claim for Your Health Benefits notes that paying anything less than 100 percent of a claim counts as a denial in part.

For plans that aren't grandfathered under the Affordable Care Act, the same guide says denial notices must include detail on the claim, the reason for denial including the denial code and its meaning, and information on internal and external appeals and consumer assistance. You can also ask for the diagnosis and treatment codes and their meanings. For job-based plans, the guide says you have at least 180 days to file an appeal of a denied claim.

The Department of Labor notes that claims are denied for various reasons: you may not be eligible, the service may not be covered, or the plan may simply need more information. If the reason isn't clear, call the plan with your claim number and ask what it needs. Our Using Your Coverage section explains formal appeals and external review.

Spotting fraud and medical identity theft

EOBs can give you early warning that someone else is using your insurance. The FTC lists warning signs that include:

A bill or EOB for services you didn't get or prescription medications you don't take.
A call from a debt collector about a medical debt you don't owe.
Medical debt collection notices on your credit report that you don't recognize.
A notice from your insurer saying you reached your benefit limit.

If you see something suspicious, CMS suggests calling your plan's fraud hotline or the member services number on your insurance card. The FTC recommends getting copies of your medical records, reporting errors to providers in writing, checking your credit reports, and creating a recovery plan at IdentityTheft.gov. Be wary of unexpected calls, emails or texts asking for your insurance details; the FTC advises logging in to your account from a website you know is real or calling a number you know is accurate instead.

Keeping EOBs organized

CMS encourages using EOBs to track how you and your family use your coverage, and to keep all paperwork in a safe place. A simple folder by year, or a downloaded copy of each EOB, makes it easier to check your deductible progress, support an appeal, or gather receipts for a health savings account or flexible spending account. When you no longer need paper EOBs, the FTC recommends shredding them, since they contain medical and insurance information.

Where to get personal help

Start with the member services number on your insurance card. For job-based plans covered by federal benefits law, the Department of Labor's Employee Benefits Security Administration offers free help at 1-866-444-3272. For individual and Marketplace plans, your state insurance department, listed in the NAIC directory, can take complaints. If you suspect identity theft, use IdentityTheft.gov.

Key takeaways

An EOB is not a bill; it explains what was billed, what the plan covered and what you may owe.
Compare each provider's bill with the EOB before paying, matching dates, services and amounts.
In-network providers may not balance bill you for covered services beyond your cost sharing.
Paying less than the full claim can be a partial denial, and non-grandfathered plans must explain denial codes and appeal rights.
Charges for care you didn't receive are a warning sign of medical identity theft; report them to your plan.

Sources

Our articles are general information, not medical, insurance, tax or legal advice, and we don't sell insurance or recommend specific plans or companies.

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