Who sends it: Your Medicare Advantage plan, Part D drug plan or other health insurer, usually in a month you used services.
What this letter is
An Explanation of Benefits, or EOB, comes from your health plan, not from your doctor. Medicare Advantage plans usually send one for each month you used services. Part D drug plans send one for each month you fill a prescription. Employer and retiree plans send them too.
If you have Original Medicare, you get a Medicare Summary Notice instead. Most EOBs say near the top that they are not a bill. The bill, if any, comes later from the doctor, hospital or pharmacy.
The words on it
- Amount billed: what the doctor or hospital asked for.
- Allowed or approved amount: the price your plan agreed to pay for that service. It is often much lower than the amount billed.
- Plan paid: what the plan paid the provider.
- You may owe, or your share: your copay, coinsurance or deductible. This is what the provider may bill you.
- On a drug plan EOB: a running total for the year, so you can see how close you are to your plan's yearly limit on what you pay for covered drugs.
What to check
- Match each line to a visit, test or prescription you really had.
- Look at the dates and provider names.
- Look for anything denied. A denial on an EOB is not the final word.
- When the bill from the provider arrives, compare it with the amount the EOB says you may owe. They should match.
- Keep each EOB with its bill until both are settled.
What to do about a problem
- A charge you do not recognize: call your plan using the member services number on your plan card and ask what the claim was for.
- If you think someone is using your Medicare number, also call 1-800-MEDICARE (1-800-633-4227).
- A denied service or drug: your plan sends a separate notice that explains your appeal rights and deadline. Ask your doctor's office to help. They can often send the plan more information.
- A bill higher than what the EOB says you owe: call the provider's billing office and read them the numbers from the EOB.
- For free help with a Medicare plan, a SHIP counselor can help. Find one at shiphelp.org.
How to tell a real one from a fake
A real EOB comes from the plan named on your member card, by mail or on the plan's own website or app. It never asks you to pay the plan through a link, a gift card or a phone call you did not expect.
Real plans do send emails saying a new EOB is ready, and scammers copy them. The safer habit is to sign in by typing your plan's website yourself instead of tapping the link.
Have one in front of you?
Take a clear photo and text it to Uncle at +1 208 214 0093. He tells you in plain words what it says, what it wants from you, and anything that looks wrong. How to take a clear photo.
This page explains what this kind of letter usually means. Your letter is the final word on your dates and amounts. For a decision about taxes, health coverage or a legal matter, call the office that sent it, using the number on its official website, or ask a professional you trust.
Read next
- Medicare Summary Notice
- Itemized hospital bill
- Medicare Annual Notice of Change
- Protect your Medicare number
- See all letters explained
Written by the Textuncle team. Last updated October 3, 2026.
Text Uncle