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What Is a Credit Card Number?

Your credit card number isn’t just a random set of digits – it’s formed using a specific formula.

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Credit card issuers use a specific formula to generate the seemingly random digits appearing on the front or back of your card. Each credit card number is strategically coded and must follow an international standard, which means these digits aren’t so random after all. 

A credit card number, typically 16-digits long, is used to identify the issuing bank, network and account holder. Every credit card number contains some generic, identifiable information, but the numerical sequence is unique to only you. Below we break down how to decipher your credit card number and what you can do to keep your credit card information safe.

What do credit card numbers mean?

Credit card numbers issued by Visa, Mastercard and Discover usually contain 16 digits, grouped in sets of four. If you have an American Express card, your number will have 15 digits, while some other cards have 19 digits. 

Here’s what some of those digits mean:

  • The first digit: The first digit of a credit card number is the Major Industry Identifier, or MII, and it indicates what type of institution issued the card. For example, American Express starts with 3, Visa with 4, Mastercard with 5 and Discover with 6.
  • The next five digits: The next sequence of digits make up the Issuer Identification Number, or IIN -- previously referred to as the Bank Identification Number, or BIN -- which identifies the financial institution issuing the card. 
  • The next nine to 12 digits: The following sequence of digits after the IIN is the individual account number. 
  • The last digit: The last digit, called a checksum, is created by a special algorithm to verify that the card is not fraudulent.

Credit card numbers vs. account numbers

The number on your credit card is different from your actual account number, which you can find on your credit card statement and never changes. In instances of theft, for example, you’ll receive a new credit card number, but your account number will remain the same. 

How to protect your credit card number

Credit card fraud is one of the most common types of identity theft in the US, according to the Federal Trade Commission. You should always avoid sharing your account information with an unknown caller and never leave copies of your credit card number around. 

In this era of online shopping, you’ll have greater security if you use a private device with a secure connection and if you double-check that the merchant’s URL is valid before entering your credit card number during checkout.  

You can use a third-party digital wallet to add an extra layer of security, which stores your payment information without using your physical card. Digital wallets like Apple Pay, Samsung Pay and Google Pay allow you to use your credit card directly from your phone with an added layer of encryption. 

You can also disguise your personal account information using a temporary virtual credit card number when shopping online. Virtual card numbers are available only with participating issuers, and you can often request one through your online account.

The bottom line

Your credit card number is strategically created to identify you, the issuer and the network. Still, following the necessary precautions can help safeguard your personal information.

Correction: An earlier version of this article was assisted by an AI engine and it used some phrases that were not entirely original. Those phrases were replaced. This version has been substantially updated by a staff writer.

The editorial content on this page is based solely on objective, independent assessments by our writers and is not influenced by advertising or partnerships. It has not been provided or commissioned by any third party. However, we may receive compensation when you click on links to products or services offered by our partners.

Liliana Hall is a writer for CNET Money covering banking, credit cards and mortgages. Previously, she wrote about personal credit for Bankrate and She is passionate about providing accessible content to enhance financial literacy. She graduated from the University of Texas at Austin with a bachelor's degree in journalism, and has worked in the newsrooms of KUT and the Austin Chronicle. When not working, she is probably paddle boarding, hopping on a flight or reading for her book club.
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