What is a credit card number?
Ever wondered what the numbers on your credit card mean? Each of those digits is necessary for transactions to take place. The numbers are used to authenticate things like the identity of the cardholder and the credit card issuer.
Credit card numbers follow a formula that’s based on the credit card issuer and network. Learn more about what these numbers mean and where to find them.
What you’ll learn
- Credit card numbers identify the credit card network, credit card issuer and cardholder.
- Other numbers you might see on a credit card are the security code and expiration date.
- Because of potential credit card scams, it’s important to help protect yourself from fraud.
- Some credit card issuers allow you to use virtual card numbers. This can help protect your credit card information when making online purchases.
What are credit card numbers and how do they work?
A credit card number is the 15- or 16-digit number found on the front or back of a credit card. It identifies several things, including:
- The credit card network: The four major credit card networks in the U.S. are Visa®, Mastercard®, American Express® and Discover®. These networks communicate between merchants and credit card issuers to facilitate credit card purchases.
- The credit card issuer: A credit card issuer is a financial institution—like Capital One and other banks and credit unions—that provides credit to cardholders. Two of the major credit card networks, American Express and Discover, are also credit card issuers.
- The cardholder: The cardholder is the person to whom a credit card is issued.
The number on your credit card is different from your account number, although the two are linked. For example, if your credit card is lost or stolen, you’ll receive a new card with a different credit card number. But the account number will stay the same.
What do credit card numbers mean?
While they might seem random, each digit on your credit card matters. Some digits have specific meanings. And others work as identifiers when grouped together.
The first six to eight digits are referred to as the bank identification number (BIN) or issuer identification number (IIN). These numbers identify the card issuer. The remaining digits identify the individual account of the cardholder.
Because each digit has meaning, it’s crucial to protect your credit card number. Avoid writing down or taking photos of the number, and always report a lost or stolen credit card to the card issuer.
Here’s a breakdown of what each number means:
First number: industry identifier
The first digit on a credit card will tell you two things: the credit card network and the industry associated with the card. For example, credit cards starting with a 3 are from American Express, while credit cards starting with a 4 are from Visa.
This chart lists the numbers’ corresponding networks:
| First digit of credit card number | Credit card network |
| 2 or 5 | Mastercard |
| 3 | American Express |
| 4 | Visa |
| 6 | Discover |
Depending on the type of card, the first digit also identifies which industry the card is associated with. This digit is the major industry identifier (MII). Some common MIIs include:
| First digit of credit card number | Industry |
| 1-2 | Air travel and financial services |
| 2-6 | Credit card networks |
| 7 | Petroleum |
| 8 | Healthcare and telecommunications |
| 9 | Government and "other" category |
Issuer identification numbers
The next five to seven digits form the rest of the BIN. These IINs can identify the credit card issuer and even the specific type of credit card.
Account identifier
The rest of the digits form a unique sequence to identify the account and cardholder. This number may change if you get a new card.
Last number: checksum
The last digit is known as the checksum or check digit. During the transaction process, this number is quickly plugged into a formula called the Luhn algorithm and used to ensure the card number is valid.
Other numbers on a credit card
The credit card number isn’t the only important information on your credit card. Here are some other numbers you’ll see:
- Expiration date: Entering a card’s expiration date can help prevent credit card fraud by adding another level of verification during purchases. And because credit cards suffer wear and tear, the expiration date ensures you get a fresh card, with any new security measures, every few years. Expiration dates are generally formatted with two digits for the month and two digits for the year, separated by a forward slash. An expiration of September 2025 would look like 09/25 on your card, for example. And it means the card should be active through the last day of September 2025.
- Security code: Sometimes called the card verification value (CVV) or card verification code (CVC), this three- or four-digit number offers additional verification for remote purchases. Retailers aren’t able to store CVV numbers, which means the code can help protect your credit account in case of a data breach. The security code can be found on the front or back of the card, depending on the issuer.
If this sounds like what you see on your debit card too, you’re right. Debit card numbers work a lot like credit card numbers, including the part about card networks, banks and cardholder identification.
How to protect your credit card information
Here are some ways to help protect yourself from credit card fraud:
- Monitor your account information online and offline. Monitoring your credit scores, credit reports and credit card statements can help you notice if something isn’t right. Keep an eye out for any suspicious activity, like transactions you didn’t make.
- If you hold on to physical documents, store them in a secure location. You can also shred papers before they’re tossed in the trash. And if you cancel a credit card account, make sure to destroy the card before throwing it away.
- Boost your digital defenses. Using a virtual private network (VPN) on your computer or smartphone can help prevent others from stealing your financial information through a public Wi-Fi network. Strong passwords for each of your online accounts can also help. And you could enable two-factor authentication for even more protection.
- Use a virtual card number. Virtual card numbers are another way to keep your credit card account more secure. These are unique credit card numbers linked to your credit card account that allow you to shop online without giving merchants your actual credit card number.
Credit card numbers FAQ
Here are some commonly asked questions about credit card numbers:
How many numbers are on a credit card?
A typical credit card number is 15 or 16 digits long. But you may see some as short as eight digits and others as long as 19. Credit cards also include other numbers, such as security codes and expiration dates.
Where is the credit card number?
You should see a string of digits placed across the front or back of the credit card in groups of three or four.
How do people steal credit card numbers?
Although credit cards are designed to help keep your information secure, there are still ways hackers try to steal card numbers. These may include phishing emails, calls or texts; large-organization data breaches; ATM skimming and other methods.
Unsecured public internet networks can also put your information at risk. Avoid entering private information like account numbers or opening sensitive documents without using a VPN. And don’t forget about paper documents—bills or bank statements may also be a risk if a fraudster goes through your mail or trash.
Curious about more ways to keep yourself and your account information safe? Learn how to protect your digital identity.
Key takeaways: credit card numbers
Credit card numbers are a string of digits on the front or back of a credit card that identify the card issuer, card network and cardholder. Because credit card numbers contain important identifying information, it’s important to keep your card number safe and keep security in mind when using it.
Interested in getting a new credit card? Check out Capital One’s comparison tool to find out which cards may be best for you. You could also see if you’re pre-approved for card offers without any impact to your credit scores.
