Credit Card Numbers: Check out what they mean
Credit Card Numbers: Check out what they mean

Have you ever wondered what those numbers on your credit card that you will never remember mean? We use our maps every day, but most of us know very little about stories and what they represent.

How to read your credit card numbers

This long number on your card contains important information. The order of numbers is not random, but is strategically organized and follows international standards.

From this sequence, you can find the issuing bank, your account number, etc. Best of all, the technology behind the numbers helps prevent fraud, minimize payment issues, and reduce errors.

As? It all goes back to when the credit card industry struggled to attract customers.

The Big Four Credit Card Networks: A Brief History

A credit card is not just a piece of plastic and metal. Everything follows strict standards. Yes, even the shape and substance of the card itself. Credit cards are powerful tools issued by financial institutions such as banks or credit unions that allow you to borrow money.

Financial institutions use third-party companies called credit card networks to facilitate communication between payment terminals and card-issuing banks. Therefore, electronic transfers are faster. The four major credit card networks dominate the global market. You know them: Visa, Mastercard, American Express and Discover.

The first and largest network was originally called “BankAmericard”. Introduced by Bank of America in 1958 as a credit product aimed at consumers rather than businesses, the card initially failed. But by the mid-1960s, it had turned a profit and racked up huge profits. By 1974, BankAmericard had expanded into international markets and in 1976 changed its name to “Visa Inc.”. Small banks responded to Bank of America’s test balloon and embraced the concept.

MasterCard, then known as the “Interbank,” appeared in 1966. By 1968, the company was operating on a global scale. In 1979, the card was renamed MasterCard. Today, this is the second largest card network in the world.

The history of American Express began in 1850 as a small freight company. By the 1950s it had grown dramatically and was expanding into finance. In 1958, American Express issued the first consumer credit card. Fun fact: These original maps were made of paper. American Express is currently the third largest credit card network in the world.


The smallest of the four card networks is Discover Card. Sears first released the Discover Card in 1985 to enter the financial markets. The map grows rapidly in a short period of time. It is now used by millions of traders worldwide.

Each of these networks has one goal: to meet consumers’ needs for instant access to money without relying on cash. Modern credit cards have a complicated and complicated history, most of which are designed to protect consumers from fraud.

First 6 digits

The first 6 digits of a credit card represent the Issuer Identification Number (IIN), also known as the Bank Identification Number (BIN). These numbers uniquely identify the card-issuing financial institution. The first number is the Primary Industry Identifier (MII), assigned by the American Banking Association. Each major credit card network has its own MII:

  • American Express cards always start with the number 3 – more specifically 34 or 37.
  • Visa cards start with the number 4.
  • Mastercard starts with the number 5.
  • Discovery cards start with the number 6.

The last 5 digits of the IIN represent the specific issuing bank. These numbers facilitate the exchange of information used to clear transactions. IINs for each of the four major networks:

  • Visa uses the numbers 2 to 6 as BINs.
  • Mastercard uses the numbers 2 and 3 or 2 to 4, 5 or 6.
  • American Express uses the numbers 3 and 4 to identify the brand of the card (e.g. American Express Platinum, Delta, etc.).

Account number

The first 6 IIN digits followed by the account number. This sequence can contain up to 12 digits, but is usually 6 digits. The issuing bank assigns this number to its individual customers. Each issuing bank has about a trillion potential account numbers.

Check Digit

Credit card issuers and networks use mathematical tools to combat data breaches and other fraudulent activities. The Luhn algorithm or modulo 10 is one such device. Developed in the 1960s, it uses identification numbers such as social security numbers and credit card numbers to determine validity.

Payment should be made by credit card immediately. For this reason, the verification process used by banks must encrypt and decrypt sensitive data immediately. This is where Luhn’s algorithm comes into play. This makes it easy to verify the card number and confirm its validity.

The Luhn algorithm is easy to use. When you add the check number to the rest of the numbers on the card, the total should be 0. If you enter a wrong number when buying online, it will be recognized immediately because the sum is not 0.


Visa uses the number 13 as the checksum in most cases, while all other major networks use the last digit.

Back of credit card

Now that we know what’s on the front of the credit card, it’s time to look at the back. Here you will usually find:

  • Security Code (CVV)
  • A magnetic strip
  • Hologram
  • Bank details and customer service phone number
  • a signature box
  • Card net sign

Some credit cards also have an expiration date on the back.

Other card numbers: CVV and expiry date

The Card Verification Value (CVV) is a series of three or four digits, usually on the back of a credit card. It represents another verification process and thus increases the level of protection. Some credit card issuers refer to this as a Card Verification Code (CVC). Regardless of its name, its purpose is the same.

By requesting this small but important additional information, the point-of-sale (POS) system can be more certain that the account holder owns the card – and that the number has not been stolen.

The card-issuing bank assigns an expiration date to the card, and can also help improve security by requiring an additional verification step. The card number may have been stolen, but without an expiration date, the card number is almost worthless.

Smart Card Technology and Magnetic Stripe

All these numbers – PAN, CVV/CVC and expiry date – are stored on the magnetic stripe and on Europay, Mastercard and Visa chips (EMV).


The magnetic strip, also known as the magnetic strip, is located on the back of the card and transmits the card’s data to the cash register. The transmitted data is static. In other words, the information is loaded into the strip and remains unchanged.

While cards still contain magnetic stripes, most of them now also use EMV or smart card technology. This microprocessor is located on the front of the card, and it also transmits data to the cash register. In contrast to static magnetic strips, EMV uses dynamic transmission.

How does it work? Every time you use the card, the transaction generates a different unique code. This process makes EMV technology more secure against card fraud, such as looting and counterfeiting.

You guessed it, everything about magnetic stripes and EMV chips is standardized by ISO.

Credit card numbers and bank account numbers

Many people think that the number on their credit card is the same as their bank account number. That is wrong. But the two are linked, and your account number is usually on your credit card statement.

If you need to replace your credit card, whether it’s stolen, lost, or damaged, you’ll receive a new card number, but your account number will remain the same.

Customer Service Phone Line

A customer service phone number is not required for purchases and will not play a role in protecting your card itself from fraud. But it’s still the best way to get in touch with a banker when you need it.

For example, many fraud attempts are made by phone or email. The quickest way to verify that a call or message is genuine is to dial the number on the back of the card. You talk to someone in the bank and he can tell you if any messages have been sent to you.

Write down this number and keep it separate from your card so that if you lose your card, you can quickly call to block the card immediately so no one can use it.

Signature field

You must sign your card before you can use it. Typically, the issuer will verify your signature when you receive it. But even if they don’t, keep that in mind, otherwise the merchant has the right to reject the card.

Hologram Security Features

Holograms are hard to fake, which is why they can be a great security feature. This little mirror-like dot shows a three-dimensional image. If you look closely, you will notice that the image moves as the viewing angle changes.

How to protect your credit card number

The sad truth is that credit card numbers are stolen all the time. The best way to avoid this is to be careful every time you buy.

Pay close attention to the platform when shopping online. If possible, use a service like PayPal to keep your credit card number safe. Otherwise check with the company, make sure the website is secure and use an SSL certificate.

Also watch out for phishing emails. If you find anything suspicious, please do not click on links or download attachments. Check the sender or call your bank. Don’t forget to keep your computer safe from malware and spyware.

Bottom line

The advent of credit card networks and improved transaction methods over the years resulted in the credit card functionality we use today. Your credit card contains important information, and while the process behind it can be complicated, it helps simplify your life and the way you pay.

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Jake Smith

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Jake Smith

He is the editor of Eragoncred. Previously, he was editor-in-chief of Eragoncred and a financial industry reporter. Jake has spent most of his career as a Digital Media journalist and has over 10 years of experience as a writer and editor.