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What Are Credit Card Numbers & What Do They Mean?

  • Credit card numbers are a sequence of 15 or 16 digits that are used to identify the cardholder, the card issuer, and the bank that issued the card.
  • The numbers on a credit card are divided into different segments that have specific meanings, such as the Major Industry Identifier (MII), the Issuer Identification Number (IIN) or Bank Identification Number (BIN), and the account identifier.

  • The last digit in a credit card number is known as the checksum, which is used to detect errors when credit card numbers are entered when making a payment.

  • To protect your credit card number, you should choose a secure password for your online account, turn on account alerts, keep your card in a safe place, never email information about your account, and avoid entering credit card details when using public internet access.

A credit card number can be 15 or 16 digits long depending on the card issuer. This number can be found on the front or back of a credit card, and it is used to portray the payment network being used, the bank that issued the card, and some identifying information of the cardholder.

That said, there’s more to credit card numbers than meets the eye, and all the numbers on a card have a specific meaning and purpose. Read on to learn how card numbers from major credit card issuers work, what they are actually used for, and everything else you should know.

What is a credit card number?

The term “credit card number” is used to describe the sequence of numbers listed on the front and the back of a credit card.

Also referred to as a card number, this series of numbers is used to identify you, your card issuer, and the bank that issued your card whenever you go to make a purchase.

You may notice that card numbers are often displayed in sets of four or five numbers listed one after another. While these numbers may seem completely random, they actually tell a story and help accurately identify you, the buyer, while helping prevent fraud.

How long is a credit card number?

The vast majority of credit card numbers are either 15 or 16 digits long, yet the type of card account plays a role in this detail. You’ll also notice that different credit card issuers choose to start their card numbers with a specific digit and that they use the same list of numbers to represent themselves thereafter.

Below you’ll find an overview of each of the major credit card issuers and how many numbers they use on their cards.

Also listed are the first digit each card issuer uses, as well as the numbers they typically use thereafter.

? First Six Digits Next Five Digits Total Number of Card Numbers
American Express Starts with 3 Uses numbers 3 and 4 15
Discover Starts with 6 Varies 16
Mastercard Starts with 5 Uses numbers 2, 3, 4, 5, and 6 16
Visa Starts with 4 Uses numbers 2, 3, 4, 5, and 6 16

The meaning of credit card numbers

According to Discover, the fact each card issuer has a minimum of 15 digits to work with means they have more than a trillion possible card number combinations they can assign to consumers.

Here’s a rundown of each sequence of numbers a credit card has, as well as how they’re used.

First number

The first six number listed on the front or back of a credit card is known as the Major Industry Identifier, or MII. As we already showed in the chart above, American Express starts their card numbers with 3, whereas numbers on a Discover card start with 6, Mastercard starts with 5, and Visa cards start with the number 4.

Identification numbers

After the first number on a credit card, the following five numbers are referred to as the card’s Issuer Identification Number (IIN) or Bank Identification Number (BIN). These numbers also help identify which credit card issuer the card is offered through and which credit card network it runs on.

Account identifier

The next sequence of numbers on the card is used to identify the actual cardholder the credit card is assigned to. That said, the length of the consumer’s actual account number will vary depending on the total length of the credit card number.

Last number: Checksum

The last digit in a credit card number is known as the checksum, and this number shows that a credit card is valid. This number is populated using a formula known as the Luhn Algorithm, and it helps detect errors when credit card numbers are entered when making a payment.

Where is the credit card number?

Credit card numbers are easy to find provided you physically possess the credit card in question.

Generally speaking, the number will be listed clearly on the front of the credit card or in the middle of the back of the card.

Front of a credit card

If you have a Discover card, you’ll find your card number clearly shared on the front of the card. Mastercard typically lists their card numbers on the front of their cards as well, although there are some exceptions.

Visa credit cards also tend to list card numbers on the front, although some of their premium travel credit cards (like the Chase Sapphire Preferred and Chase Sapphire Reserve) have card numbers on the back.

Back of a credit card

American Express credit card numbers are always located on the back of the card.

Other card numbers: The CVV and expiration date

You can find a few other card numbers clearly displayed, although these numbers are not your actual account numbers. Specifically, we are talking about the CVV and the credit card expiration date.

The CVV is a credit card security code that is three to four digits long and printed on the front or the back of a credit card. Where Discover, Mastercard, and Visa have three-digit CVV numbers printed on the back of the card, Amex credit cards have four-digit security codes that are printed on the front.

When it comes to a credit card’s expiration date, it is typically listed in the (MM/YY) format on the back of a credit card. If a card expires in September of 2027, for example, the expiration date will be listed as 09/27.

Other credit card features

Several other credit card features can change the look and feel of your credit card or make purchases safer or more convenient.

Here’s a rundown of some common card features you should know about.

Chip card technology and magnetic stripes

Where older credit cards embed important payment information in a magnetic stripe you “swipe” at the point of sale when making a purchase, others have EMV chip technology that lets you insert or “dip” your credit card into the payment terminal.

Some cards also offer contactless payment options, so you can simply tap your card against the terminal and pay that way.

Customer service phone line

Your credit card will almost certainly have a customer service number listed, which you can call 24/7 with inquiries and questions about your card. If you have a co-branded credit card that’s associated with a frequent flyer program, a hotel loyalty program, or another third-party loyalty program, you may also see a customer service number related to that program as well.

Signature box

The signature box on the back of your credit card is where you sign your name if you want to. Merchants are supposed to compare signatures when you use your card for a transaction that requires one, and not signing your card means it’s more likely you’ll be asked to show identification for in-person transactions.

Hologram security feature

Many credit cards also have a hologram security feature that is made to appear three-dimensional. The purpose of this feature is to prove that a card is genuine and not a counterfeit.

Note that not all credit cards have a hologram security feature, including most American Express credit cards.

5 tips for protecting your credit card number

Keeping your card number private is the best way to avoid having fraudulent purchases show up on your account.

However, you should also know that credit cards come with the best consumer protections among all forms of payment.

In fact, consumers who see fraudulent charges show up on their credit cards are typically protected with $0 liability for fraud policies. Further, the Federal Trade Commission (FTC) notes that federal law limits liability for credit purchases to $50 total if the fraud is reported after the card’s use was noticed.

That being said, you can limit your risk of becoming a victim of credit card fraud with the following tips:

1

Choose a secure password for your online account.

Make sure you choose complex passwords that can’t be easily guessed for all your online accounts, including online bank accounts and credit card accounts.

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2

Turn on account alerts.

Most credit card companies let you set up alerts that notify you when a purchase is made. You can typically set up these alerts on a new card or one you already have.

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3

Keep your card in a safe place at all times.

Store your credit card in a safe place where people cannot easily access it, including visitors in your home.

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4

Never email information about your account.

Never send sensitive personal information, including credit card details, through email or personal messages.

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5

Don’t enter your credit card details using public internet access.

Only make online purchases at home, or when you can, use a secure website or a VPN.

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FAQ: Credit card numbers

What is a credit card number?

A credit card number is a sequence of numbers listed on the front or the back of a card. This number is unique to each cardholder, although each credit card issuer has a set routine for how their numbers are assigned.

How long are credit card numbers?

Credit card numbers are typically 15 or 16 digits long, depending on the card issuer.

What is a virtual card number and how does it work?

Virtual card numbers are card numbers you can use that don’t require you to share your actual credit card number when making a purchase online. Using them makes online shopping much more safe and secure, and many card issuers offer virtual numbers upon request.

How do people steal credit card numbers?

People steal credit cards using credit card skimmers and sophisticated hacking techniques. Some thieves also steal card numbers by accessing physical credit cards and taking a photo or writing down their information. Always be cautious when using your card at a point of sale.

Do credit cards have routing numbers?

Credit cards do not have routing numbers, but checking accounts and savings accounts do.

What to do if my card number has been stolen?

If your credit card number has been stolen, you should call your credit card issuer to report the problem right away. Some credit card issuers also let you freeze your account to avoid new charges online or through their mobile app.

How do I read my credit card number?

Read your credit card number from left to right, whether listed on the front or back of your card.

About the Author

Holly D. Johnson
Holly D. Johnson Finance Expert

Holly D. Johnson is an award-winning personal finance writer who covers topics like insurance, investing, credit and family finance. As a leading voice in the travel and loyalty space, Johnson has traveled with her family to more than 50 countries over the last decade.

The author has also written extensively on the power of household budgeting, and she even co-authored a book on the topic. Zero Down Your Debt: Reclaim Your Income and Build a Life You’ll Love was originally published in 2017, and it teaches families how to use zero-sum budgeting to reach their financial goals. She is also the co-owner and founder of the family finance and travel website, ClubThrifty.com.

Johnson’s 10+ years of writing have focused on helping families make important financial decisions at each stage of their lives. The author also applies the financial principles she teaches to her own life, and she is currently on track to retire in her late 40’s with her partner. She currently lives in Central Indiana with her husband and children, and she is a regular contributor for Bankrate, CNN, Forbes, U.S. News and World Report Travel and many other notable publications.

* Opinions expressed here are those of the LA Times Compare Cards Team and have not been reviewed or approved by any advertiser or entities included within this content. See our editorial policy for more details.

All products or services are presented in this content without warranty. The information, including card details such as rates and fees, is accurate at the time of publish. Please visit each bank's website directly for the most current information.

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