Medicare Summary Notice (MSN): How to Read It and What to Do

Written by Theodore Nguyen-Cao, Founder of Plainly. Published November 9, 2026. Facts checked against official sources on November 11, 2026.

This guide was accurate as of November 11, 2026. Rules, amounts, deadlines, and phone numbers can change after that date, so follow the letter you received and check the official sources listed below.

The short answer

A Medicare Summary Notice (MSN) is a statement for people with Original Medicare listing the services billed to Medicare, what Medicare paid, and the most you may be billed. It is not a bill. Check it against your receipts, report anything you do not recognize, and appeal any denial by the date printed on it.

Is this letter real?

Medicare’s own page on the Medicare Summary Notice says the paper MSN arrives every 6 months if you got any services or medical supplies during that period. If you switched to electronic MSNs, you get an email with a link for any month you have a processed claim, instead of paper copies (Medicare.gov).

Signs of a genuine MSN:

It is titled “Medicare Summary Notice” and says “THIS IS NOT A BILL” at the top of every page.
It shows your name, your Medicare Number, the date of the notice, and the period the claims cover.
It never asks you to pay Medicare or to send payment to an address on the notice.

Scams often borrow Medicare’s name. CMS, the agency that runs Medicare, says Medicare will never call you uninvited to ask for personal information, such as your Medicare Number (CMS). If anyone contacts you about your MSN and asks for your number or money, hang up and call 1-800-MEDICARE (1-800-633-4227) yourself. TTY users can call 1-877-486-2048 (Medicare.gov). You can also see your claims at any time by logging in to your account on Medicare.gov.

One more check: the MSN is for Original Medicare. If you are in a Medicare Advantage plan or a separate drug plan, your plan mails you an Explanation of Benefits for those claims instead of an MSN (Medicare.gov).

What the letter says, section by section

There are separate MSNs for Part A (hospital insurance) and Part B (medical insurance), and you may get one for medical equipment and supplies. The layout below follows CMS’s Part B sample MSN.

Page 1: your dashboard

Your information: your name, Medicare Number, the date of the notice, and the date range of claims processed.
Your deductible status: how much of this year’s deductible you have met. The deductible is the amount you pay for most services before Medicare starts to pay.
Your claims and costs this period: a yes or no answer to “Did Medicare approve all services?”, the number of services denied, and the total you may be billed.
Providers with claims this period: the doctors and facilities that billed Medicare, with dates.

Page 2: how to check this notice

Tips for reviewing the notice, information on preventive services, how to report fraud, and how to get help. This page also lists the phone number for your State Health Insurance Assistance Program (SHIP), which gives free, local Medicare counseling.

Page 3 onward: your claims

A table for each claim. The columns, as CMS defines them:

Service approved? Yes or no. Look for “NO” here first.
Amount provider charged: the provider’s fee.
Medicare-approved amount: what a provider can be paid for that service. It may be less than the amount charged.
Amount Medicare paid: usually 80 percent of the approved amount for Part B services.
Maximum you may be billed: the most the provider is allowed to bill you. It can include your deductible, coinsurance, and charges Medicare did not cover. If you have a Medigap policy or other insurance, it may pay some or all of this.
See notes below: letters that point to explanations, such as why a service was denied or that the claim was sent on to your Medigap insurer.

Last page: how to handle denied claims or file an appeal

Step-by-step appeal instructions, the mailing address of the Medicare claims office (contractor) that processed your claims, and a specific date by which they must receive your appeal. That date is printed on your notice. Use it.

What to do next

Compare the MSN with your records. Medicare suggests comparing it with your receipts and bills. Ask: do I recognize each provider, did I have an appointment that day, and did I get each service listed?
Do not pay anything to Medicare. Pay only bills from your providers, and only up to the “maximum you may be billed.” If you already paid a provider more than that, call the provider and ask about it.
If something looks wrong, call the provider first. CMS’s sample MSN suggests asking the provider for an itemized statement and checking they sent the right information. If they did not, ask them to contact the Medicare claims office to correct the error.
If you suspect fraud, report it. Call 1-800-MEDICARE or use Medicare’s fraud reporting page. Examples include bills for services you never got.
Appeal a denial by the deadline. CMS says you have 120 days from the date you receive the notice to ask for a “redetermination,” the first level of appeal. Medicare assumes you got the notice 5 days after the date printed on it (CMS). There is no minimum dollar amount. You can appeal in either of two ways:
- Follow the instructions on the MSN’s last page: circle the items you disagree with, explain why in writing, add your name, phone number, and Medicare Number, and mail it with copies of supporting documents to the address shown.
- Or fill out the Medicare Redetermination Request Form (CMS-20027) and send it to the same contractor.
Include support. Medicare.gov suggests adding anything that may help your case, like a doctor’s note explaining why you needed the service. Write your Medicare Number on every page and keep copies of everything.
Wait for the decision. The contractor generally decides within 60 days. If you disagree with that decision, there are four more levels of appeal, and the decision letter explains how to request the next one (Medicare.gov).

If you do nothing, the MSN simply becomes part of your records. But if a claim was denied and you miss the deadline, you may lose the chance to appeal. Medicare.gov says you may still be able to file late if you have good cause, such as illness or an accident.

Common mistakes

Treating the MSN as a bill. Medicare does not collect money through it.
Paying more than the “maximum you may be billed.” That column is your ceiling for that service.
Paying before checking Medigap. If a note says the claim went to your supplement plan, wait to see what it pays.
Throwing it away unread. It is your best tool for spotting errors and fraud.
Missing the appeal date. The exact “we must receive your appeal by” date is on the last page.
Updating your address with the wrong office. CMS’s sample MSN says to report a change of address to Social Security at 1-800-772-1213 (TTY 1-800-325-0778).

Where to get free help

1-800-MEDICARE (1-800-633-4227), TTY 1-877-486-2048: questions about claims, coverage, and appeals.
State Health Insurance Assistance Program (SHIP): free, one-on-one Medicare counseling. Your MSN lists your SHIP’s phone number on page 2, or find yours at shiphelp.org.
Senior Medicare Patrol (SMP): help spotting and reporting Medicare fraud and billing errors. Find yours at the SMP Resource Center.
A family member or friend: the MSN notes you can appoint someone to represent you in an appeal.
Have a private plan instead? See our guide to an Explanation of Benefits.

How Plainly helps

A Medicare Summary Notice lists every service in small print, across several pages of codes and columns. Plainly turns it into plain English, quickly. Take a photo of each page of your MSN (up to five pages) and Plainly tells you:

What it is: the period and services it covers.
What it wants from you: whether you need to do anything (often nothing).
Your deadline and how urgent it is: deadlines such as the appeal date.
The numbers that matter: what Medicare approved and the most you may be billed.
Anything that looks off: possible scam signals worth checking before you pay or call anyone.
What it could not read: parts of your photo that were not clear, so you know what to double-check.

You can listen to the explanation read aloud, share it with someone who helps you, and find it later in My Scans on your device. It works on the web, iOS, and Android, needs no account, and Plainly does not store your photos.

Plainly can make mistakes, so check dates and amounts against your MSN before you act.

Scan your MSN with Plainly

Frequently asked questions

Is a Medicare Summary Notice a bill?

No. Medicare says the MSN is not a bill. It shows what was billed to Medicare and what Medicare paid. Your provider sends any bill separately.

How often do I get a Medicare Summary Notice?

Medicare.gov says paper MSNs come every 6 months if you got services in that period. With electronic MSNs, you get an email for any month with a processed claim.

How long do I have to appeal a denied claim on my MSN?

120 days from when you receive the notice, according to CMS. The exact date is printed on the last page of your MSN.

What does “maximum you may be billed” mean?

It is the most your provider is allowed to bill you for that service, including your deductible, coinsurance, and anything Medicare did not cover. Supplement insurance may pay part of it.

What should I do if I see a service I never received?

Call your provider to ask about it. If it still looks wrong, report it to 1-800-MEDICARE or your local Senior Medicare Patrol.

Plainly explains documents in plain language. It is not legal, tax, medical, or financial advice. Always check important dates, amounts, and contact details against the original letter.