How to Find or Replace Your Medicare Number

Where to find your Medicare number if you already have one

Your Medicare number is printed on your Medicare card, which arrives in the mail after you turn 65 and enroll. If you have the card, look at the front — your number appears in the upper left corner, followed by a letter. That is your Medicare number, and you will need it every time you see a doctor, fill a prescription, or contact Medicare.

If you cannot find your card but remember your Social Security number, you can look up your Medicare number online through your Medicare account at Medicare.gov. Go to the "Sign In" button, create an account or log in with your existing one, and your number will appear in your account dashboard. You do not need to call anyone to do this.

Your Medicare number stays the same for life, unless you request a new one. It does not change if you move, change doctors, or switch Medicare plans.

Key Takeaways

Your Medicare number is on the front of your Medicare card in the upper left corner, followed by a single letter.
You can look up your number online at Medicare.gov by signing into your account without calling Medicare.
If your card is lost or damaged, you can request a replacement card by phone, mail, or online.
A replacement card takes 7 to 10 business days to arrive by mail, or you can view your number when ready online while you wait.
Your Medicare number does not change unless you request a new one, even if you move or change plans.

How to get a replacement Medicare card

If your card is lost, stolen, or damaged, you can request a replacement through three routes: online, by phone, or by mail. The fastest is online through your Medicare account at Medicare.gov. Log in, go to "Manage Your Health Care," select "Order a replacement Medicare card," and follow the prompts. You will see your number on screen when ready, and a new card will arrive in 7 to 10 business days.

If you do not have an online account or prefer to call, dial 1-800-MEDICARE (1-800-633-4227). A representative will verify your identity using your name, date of birth, and Social Security number, then mail a replacement card to your address on file. This also takes 7 to 10 business days.

You can also request a replacement by mail. Fill out Form CMS-582, which you can read from Medicare.gov or request by calling 1-800-MEDICARE. Mail the completed form to the address on the form itself. This route is slower — allow 2 to 3 weeks — but works if you have no internet access and prefer not to call.

What to do if you never received a Medicare card

If you enrolled in Medicare but your card never arrived, first check your mail for 2 to 3 weeks after your enrollment date. Medicare cards are mailed automatically, but mail delays happen. If you still have not received it after that window, log into your Medicare account at Medicare.gov and check your account dashboard — your number will be there even if the physical card has not arrived.

If you need the card itself (some doctors or pharmacies still ask for the physical card, though this is becoming less common), request a replacement using the online method or by calling 1-800-MEDICARE. Tell the representative that you never received your original card, and they will send a replacement to your address.

Do not assume your enrollment failed because the card is late. Your Medicare coverage is active on your enrollment date regardless of when the card arrives. You can see your coverage details in your online account when ready.

Understanding the parts of your Medicare number

Your Medicare number has two parts: an 11-digit number and a single letter at the end. The 11-digit number is unique to you. The letter — usually A, B, C, or D — indicates your relationship to Social Security. If you enrolled based on your own work record, your letter is usually A. If you enrolled as a spouse, it may be B. The letter does not affect your coverage; it is just a record-keeping code.

Starting in 2024, Medicare began issuing new cards with a different format. The new cards use a random 11-digit number instead of your Social Security number, which improves privacy. If you receive a new card, your old number stops working. The transition is gradual, so you may still have an old-format card for now. Both formats are valid until the old cards expire.

Using your Medicare number for prescriptions and doctor visits

When you see a doctor or fill a prescription, have your Medicare card ready or be prepared to give your Medicare number. Doctors' offices and pharmacies use this number to check your coverage and process claims. If you do not have your card with you, you can give the number verbally — it is safe to share with healthcare providers.

Some online pharmacies and telehealth services ask for your Medicare number before your first visit. You can provide it over the phone or through a find online form. Never share your Medicare number by email or text unless you initiated the contact with a healthcare provider you trust.

What to do if your Medicare number was compromised

If you believe someone has stolen or misused your Medicare number, contact Medicare when ready at 1-800-MEDICARE (1-800-633-4227). A representative can review your account for fraudulent claims and help you monitor for misuse. You can also check your account online at Medicare.gov to see a list of claims submitted in your name — if you see claims you did not authorize, report them to Medicare right away.

Medicare can issue you a new number if fraud is confirmed, though this is uncommon. A new number means a new card and a new Medicare number for life, so it is only done when necessary. In most cases, Medicare will straightforward flag your account and monitor it for further suspicious activity.

Frequently Asked Questions

Can I use my Social Security number instead of my Medicare number?

No. Your Medicare number is separate from your Social Security number. Doctors, pharmacies, and Medicare itself require your Medicare number, not your Social Security number. If you have an old Medicare card with your Social Security number on it, that number is no longer valid — request a replacement card with your new random number.

What if I lost my Medicare card and do not have internet access?

Call 1-800-MEDICARE and ask for a replacement card. A representative will mail one to you in 7 to 10 business days. While you wait, give the representative your Medicare number over the phone so you have it written down for doctor visits and prescriptions.

Does my Medicare number change if I switch from Original Medicare to a Medicare Advantage plan?

No. Your Medicare number stays the same no matter which plan you choose. The number is tied to your Medicare enrollment, not to a specific plan. Your plan name and coverage details change, but your Medicare number does not.

Is it safe to give my Medicare number to my doctor?

Yes. Your doctor needs your Medicare number to verify your coverage and submit claims. It is safe to share with any healthcare provider, hospital, or pharmacy. Do not share it with anyone who contacts you unsolicited claiming to be from Medicare.

What if I have both an old and new Medicare card?

Use only the new card. If you received a new card with a random number, your old card with your Social Security number is no longer valid. Destroy the old card by cutting it up. If a doctor's office has your old number on file, you can update it by giving them your new number.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.