What is Medicare member ID called?

Editorial team Published on

Medicare refers to the insured's identification number as the Medicare Beneficiary Identifier (MBI).

Overview of Medicare ID Terms

  • Medicare Beneficiary Identifier (MBI): The current, unique identification number that Medicare uses on beneficiary cards instead of Social Security-based numbers.
  • Health Insurance Claim Number (HICN): The older term for the Medicare identification number, which was historically based on the beneficiary's Social Security number before the transition to MBIs.

What is my Medicare member ID?

Your Medicare member ID—officially called the Medicare Beneficiary Identifier (MBI)—is an 11-character combination of numbers and uppercase letters found on the front of your red, white, and blue Medicare Card.

How to Find Your Medicare Number

  • Physical Card: Look on the front of your official red, white, and blue Original Medicare card.
  • Online Account: Log in to your official Medicare Account to view your profile and ID details.
  • Social Security: Check your Benefit Verification Letter by signing into your My Social Security Account.
  • By Phone: Call Medicare directly at 1-800-MEDICARE (1-800-633-4227) to verify your identity and retrieve your number.

Important Distinctions

  • Not your SSN: Your MBI is randomly generated and distinct from your Social Security number to protect your identity.
  • Original vs. Advantage: If you belong to a private Medicare Advantage (Part C) plan, you will also have a separate private plan member ID card to use for day-to-day doctor visits.

Is Medicare Part A and B the same ID number?

Yes, Medicare Part A and Part B use the exact same ID number, known as your Medicare Number or Medicare Beneficiary Identifier (MBI).

📌 Your Medicare ID

  • Single identifier: Both parts share one 11-character alphanumeric ID.
  • One card: They appear together on your red, white, and blue card.
  • Not your SSN: It is entirely separate from your Social Security number.

🗓️ Coverage Details

  • Separate dates: The card lists individual start dates for Part A and Part B if you enroll at different times.
  • Labeled clearly: Part A is listed as HOSPITAL and Part B as MEDICAL.

What does a Medicare ID look like?

An official Medicare ID number—known as the Medicare Beneficiary Identifier (MBI)—is an 11-character alphanumeric code made up of randomized uppercase letters and numbers.

What the ID Number Looks Like

  • Format: It looks like this example: 1EG4-TE5-MK73.
  • Structure: The 2nd, 5th, 8th, and 9th characters are always letters. The rest are numbers or letters.
  • Characters used: It uses numbers 0-9 and letters A through Z, but excludes letters S, L, O, I, B, and Z to prevent confusion.
  • No hidden meaning: The characters are completely random and do not contain your Social Security number or personal data.

What the Card Looks Like

  • Material: It is printed on plain paper, not plastic, so doctors can easily make photocopies.
  • Design: It features a blue banner at the top (with "Medicare Health Insurance") and a red stripe at the bottom, with a white background in the middle.
  • Information on the card: It shows your full name, your unique 11-character Medicare ID number, your coverage types (Hospital Part A and/or Medical Part B), and the date your coverage started.

You can view details or print a replacement from your Official Medicare Account.

Is Medicare number the same as member ID?

Your Medicare number is generally not the same as a private plan member ID, unless you are referring strictly to your official Medicare ID number.

Medicare Number vs. Member ID

  • Medicare Number (MBI): This is your unique 11-character alphanumeric identifier issued by the federal government and printed on your red, white, and blue Medicare Card. It is officially called the Medicare Beneficiary Identifier (MBI) and is used for Original Medicare (Parts A and B).
  • Member ID: If you have a private insurance plan—such as a Medicare Advantage plan (Part C), a Medicare prescription drug plan (Part D), or a Medigap supplement plan—that private company issues its own separate insurance card with its own unique Member ID.

Key Differences

  • Original Medicare: Uses your federal Medicare Number (MBI) for billing and claims. It does not use a private "member ID".
  • Medicare Advantage / Part D: You will use the member ID provided on your private insurance company's card when you go to the doctor or pharmacy, though providers may still ask for your federal Medicare number in certain situations.

Get to Know Your Medicare Advantage Member ID Card

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How to look up a Medicare ID number?

You can find your Medicare ID number (called a Medicare Beneficiary Identifier or MBI) online by logging into your Social Security Account.

Find It Online via Social Security

  • Log in to your personal account on SSA.gov.
  • Go to the benefits section and look for Get a Benefit Verification Letter.
  • Open or download the PDF letter.
  • Find your Medicare number and start dates listed in the Medicare section.

Find It via Medicare.gov

  • Log in to your personal Medicare Account if you already set one up.
  • Your profile or dashboard will display your active coverage details and ID number.

Other Ways to Get Your Number

  • Check old notices: Look at past Medicare Summary Notices (MSNs) mailed to your home.
  • Call customer service: Call 1-800-MEDICARE (1-800-633-4227) to speak with a representative who can help verify your identity and provide your number.
  • Request a replacement card: If your card is lost, order a new physical card through your Social Security or Medicare online account.

Can I lookup my Medicare number with my social security number?

You cannot directly type your Social Security Number into an instant lookup tool to find your Medicare number, but you can use your Social Security Administration (SSA) account to find it online.

How to Find Your Medicare Number Using Your SSA Account

  • Log In: Sign in to your account at SSA.gov.
  • Access the Letter: Look for your Benefit Verification Letter.
  • View Details: Open the letter to find your Medicare start dates and your unique Medicare number (also called your Medicare Beneficiary Identifier or MBI).

Other Ways to Locate Your Number

  • Online Medicare Account: Log into your secure Medicare account to view or print an official copy of your card.
  • Call Support: Contact 1-800-MEDICARE (1-800-633-4227) for personal assistance.
  • Check Past Mail: Look at previous Medicare Summary Notices (MSNs) or official health benefit statements sent to your home.

What is a Medicare ID number called?

The Medicare number is officially called the Medicare Beneficiary Identifier (MBI).

About the MBI

  • Format: It is an 11-character code made up of numbers and uppercase letters.
  • Security: It is completely unique to you and is not your Social Security number.
  • Location: You can find your MBI printed on the front of your red, white, and blue Your Medicare Card.

Why do I have two Medicare numbers?

You likely have two Medicare numbers because you were recently issued a new Medicare Beneficiary Identifier (MBI) due to security updates, or because you have a combination of Original Medicare, a Medicare Advantage plan, or past spousal/own work history numbers.

🔎 Common Reasons For Multiple Numbers

  • 🛑 Security Reassignment: CMS periodically reassigns new MBIs (Medicare numbers) due to data breaches or fraud protection.
  • 📋 Plan vs. Original ID: You might be confusing your Original Medicare number with a separate Medicare Advantage or Part D plan card ID.
  • 👥 Spousal vs. Personal: You may have been assigned a number under your own Social Security number and another under a spouse's record.

💡 What You Should Do Next

  • 📅 Check dates: Look at the issue dates or letters accompanying the cards to see which one is the most recent.
  • 📞 Call support: Contact Official Medicare Support at 1-800-MEDICARE to verify which number is currently active.
  • ⚠️ Shred the old card: Once you confirm your active number, securely destroy the outdated card to prevent billing errors or fraud.

Are Medicare ID numbers changing in 2026?

No, Medicare ID numbers are not changing for everyone in 2026, but 1.3 million affected people received new numbers according to the Center for Medicare Advocacy.

Who Is Affected

  • 1.3 million people: Only a small group of beneficiaries received new Medicare Beneficiary Identifier (MBI) numbers.
  • Security reason: This change happened because of data security concerns or vendor breaches that exposed certain numbers.
  • Most people: If you did not get a letter in the mail, your current Medicare card and number are still active and unchanged.

Timeline

  • March 2026: New cards were mailed out.
  • April 14, 2026: The new numbers became officially active, and old numbers stopped working for claims.
  • Benefits: Your coverage, premiums, and health plans do not change.

What You Should Do

  • Update doctors: Give your new Medicare number to your doctors and pharmacies so your claims do not get denied.
  • Destroy old cards: Shred your old paper card right away.
  • Watch for scams: Medicare will never call you on the phone to activate a new card or ask for personal details.