How to Read Your Medicare Explanation of Benefits Letter
Your Medicare EOB is not a bill. Learn what each section means, how to spot errors, and how to find EOBs online.
At a Glance
Find the "This is not a bill" notice
~18sCheck the provider name and service date
~26sWarning
An unfamiliar provider or a date when you did not receive care can be a sign of billing fraud or a medical identity theft attempt. Call 1-800-MEDICARE to report it.
Read the four key dollar columns
~28sQuick Tip
Do not worry that the billed amount looks enormous. What matters is the "You may owe" column. That is the number to compare against any bill you receive from the provider.
Look for any denied services
~18sCompare the EOB to any bills you receive
~27sQuick Tip
If you have a Medigap (supplemental) plan, that plan should also send you an EOB. Your out-of-pocket cost may be zero after both plans process the claim.
View your EOBs online at Medicare.gov
~30sQuick Tip
Your Medicare number is on the front of your Medicare card. It is a combination of letters and numbers, not your Social Security number.
Appeal a denied claim within the deadline
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After you use a Medicare-covered service — a doctor visit, a lab test, a hospital stay — you will receive a letter in the mail called an Explanation of Benefits, often shortened to EOB. This letter can look confusing at first because it has many columns and numbers. But once you know what each part means, it becomes a useful tool for protecting your health and your money.
## The Most Important Thing to Know First: An EOB Is NOT a Bill
Many people receive their EOB and panic because they see large dollar amounts. Do not pay anything based on an EOB alone. The EOB shows you what happened with your insurance claim. An actual bill — if you owe anything — comes separately from your doctor or hospital. If you are ever unsure whether something is a bill or an EOB, look for the words "This is not a bill" printed on the document. Medicare EOBs always include that notice.
## What Medicare Sends You
If you have Original Medicare (Part A and Part B), Medicare mails you a document called a Medicare Summary Notice (MSN) every three months. This is your version of an EOB. It lists every service Medicare processed for you during that quarter.
If you have a Medicare Advantage plan (Part C — a plan from a private insurer like Humana, Aetna, or UnitedHealthcare), your insurance company sends you an EOB, usually after each claim is processed.
## What Each Section of the EOB Means
Provider name and service date.
This tells you who billed Medicare and when the service happened. Check that you recognize the provider and the date. If you see a provider you never visited, that is a red flag for billing fraud.
What was billed.
The dollar amount the doctor or hospital charged for the service. This is almost always higher than what Medicare actually pays.
Medicare-approved amount.
The amount Medicare agreed to pay for that service. Doctors who accept Medicare (called "participating providers") have agreed in advance to accept this amount as full payment.
What Medicare paid.
The portion Medicare sent directly to the provider. For most Part B services, Medicare pays 80 percent of the approved amount.
What you may owe.
The remaining portion — usually 20 percent of the approved amount for Part B — that Medicare expects you to pay. If you have a Medigap (supplemental insurance) plan, that plan often covers this 20 percent. Check your EOB against any supplemental insurance statements you receive.
Denial reasons.
If a service was not covered, the EOB will show a reason code. Common reasons include the service not being medically necessary, a billing code error, or the provider not being enrolled in Medicare.
## Why You Should Keep Your EOBs
Keep your EOBs for at least one year, ideally three years. You will need them if: - A bill arrives and you want to confirm Medicare already paid its share - You suspect a billing error - You are appealing a denied claim - You are doing your taxes and tracking medical expenses
A simple system: put each EOB in a folder labeled with the year as it arrives. At the end of the year, move the folder to a drawer and start a new one.
## How to Find Your EOBs Online
You do not have to wait for paper mail. Visit Medicare.gov and log in with your Medicare account (or create one). Go to "My Account" and then "Claims and EOBs." You can view, download, and print your EOBs from the last 36 months at any time.
## How to Appeal a Denied Claim
If Medicare denies a service you believe should be covered, you have the right to appeal. The EOB will include instructions and deadlines. You must file a Redetermination (the first level of appeal) within 120 days of receiving the denial notice. Call 1-800-MEDICARE (1-800-633-4227) for help starting the appeal process.
## Official Sources
- Medicare.gov official site: medicare.gov
- 1-800-MEDICARE helpline: 1-800-633-4227 (TTY: 1-877-486-2048)
- AARP Medicare Resource Center: aarp.org/health/medicare
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