A Guide to Credit Card Number Format and Security

A credit card number is a 16-digit code that identifies you as the cardholder. This code is made up of a combination of numbers that follow a specific format.

The first digit, also known as the Major Industry Identifier (MII), is used to identify the type of card issuer. For example, a card issued by a bank starts with a 5.

The next 6 digits, known as the Primary Account Number (PAN), are unique to each cardholder and are used to identify the account. The last 9 digits, also known as the Check Digit, are calculated using a formula that involves the other 15 digits.

Using a credit card number that's not in the standard 16-digit format can lead to declined transactions and other issues.

A credit card is a type of loan that gives you access to a line of credit.

The most common type of credit card is the revolving credit card, which allows you to make purchases, pay off balances, and reuse the credit line.

Credit cards have a unique 16-digit number, also known as the Primary Account Number (PAN), that identifies the cardholder and the issuing bank.

The PAN is usually printed on the front of the card, separated into four sections by spaces.

The card expiration date is usually printed on the front of the card, in the format MM/YY, and indicates the last date the card can be used.

The credit limit is the maximum amount you can charge on your credit card, and it's usually printed on the card or available on your account statement.

A credit card number is made up of 16 digits, but did you know that the first digit, known as the Major Industry Identifier (MII), can tell you what type of company a card is affiliated with? This could be an airline, a banking institution, or a retailer, for example.

The first digit also helps indicate which major card network the card belongs to, such as American Express (3), Visa (4), Mastercard (5), or Discover (6).

The first six digits of a credit card number, known as the Bank Identification Number (BIN) or Issuer Identification Number (IIN), identify the issuer of the card. This is used to route payment instructions to the correct network and its member bank or credit union.

Here's a breakdown of the first digit's meaning:

A credit card is a type of payment card issued to users as a system of payment.

It allows cardholders to pay for goods and services based on the promise to pay later, rather than with immediate payment through cash or a debit card.

The card itself is made up of a magnetic stripe or a chip, which stores the cardholder's account information.

This information includes their name, account number, expiration date, and security code.

The card is also embossed with the cardholder's name and account number, making it easier to identify the card.

The credit limit is the maximum amount a cardholder can charge on their card, and it's set by the credit card issuer.

Credit cards can be categorized into different types, including cashback, rewards, and balance transfer cards.

Each type of credit card has its own benefits and drawbacks, which cardholders should consider before applying for a card.

Cardholder data, or CHD, is made up of several key components. The full Primary Account Number, or the 16-digit card number (or 15-digit for American Express), is a crucial part of this data.

The Primary Account Number is used to identify the individual account in question, and it can have as many as 12 digits. This number will change when you get a replacement credit card because the original was lost or stolen, but it won't affect your credit score.

Expiration Date, Cardholder Name, and Service Code are also part of the Cardholder Data. The Service Code is a specific code that identifies the type of card and the benefits available to cardholders.

Here's a breakdown of the key components of Cardholder Data:

This information can be stored on file with the proper controls in place, allowing merchants to reinitiate transactions when combined with the necessary authorization request.

The Card Verification Code (CVC) or value (CVV) are different terms used by Visa and Mastercard to refer to the same 3-digit or 4-digit security code on a plastic card.

Both CVC and CVV are considered sensitive authentication data and cannot be stored by merchants.

A CVC or CVV adds another layer of protection for card-not-present transactions, ensuring those without your physical card can't easily use it for other online purchases.

American Express is the only major credit card network to have the CVV as 4 digits, while credit cards from Visa, Mastercard, and Discover have a 3-digit CVV.

The CVV is used to authenticate your card during a transaction, serving the same purpose regardless of whether it's 3 or 4 digits.

A security code (aka CVC or CVV) is a unique string used to verify the authenticity of a transaction, typically located on the back of a payment card.

This code is not embossed on the card itself, making it a bit more difficult for bad guys to obtain.

The Luhn algorithm is a clever way to validate primary account numbers, including credit card numbers, using a Mod 10 checksum.

The final digits of your credit card number is a check digit, akin to a checksum, which can be calculated using the Luhn algorithm.

To calculate the Luhn algorithm by hand, you start by writing down the credit card number, like this: 4417 1234 5678 9113.

Doubling every other digit is the next step, resulting in numbers like 8, 2, 2, 6, 10, 14, 18, and 2.

If the result of the doubling ends up with a two-digit number, you add those two digits together, like 10 becoming 1+0 and 14 becoming 1+4.

The final step is to add up all the numbers, including the doubled ones, and see if the sum is divisible by 10.

If the final sum is divisible by 10, then the credit card is valid, but if it's not, the number is likely invalid or fake.

The first six to eight digits in a credit card number are known as the Bank Identification Number (BIN) or Issuer Identification Number (IIN).

The BIN routes payment instructions to the correct network and its member bank or credit union.

The Major Industry Identifier (MII) is the first digit of the BIN and PAN, and it indicates to processors which card brand to send the payment for further processing.

There are 10 MII, but you're likely only to need to know four of them.

Here's a list of the most common MII:

The card networks use the remaining BIN digits to determine which financial institutions to route the transaction for further processing.

To ensure the security and validation of credit card numbers, it's essential to follow the Luhn algorithm, which checks the number against a set of rules to verify its validity.

The Luhn algorithm works by doubling the value of every second digit from right to left, then summing up the digits. This process helps to detect errors and invalid numbers.

A valid credit card number must have a check digit at the end, which is calculated using the Luhn algorithm. The check digit is usually the last digit of the number.

The length of a credit card number can vary, but it's typically between 13 and 19 digits. American Express cards, for example, have a 15-digit number.

Credit card numbers can tell you a lot about the type of card and the issuer. The first digit, known as the Major Industry Identifier (MII), indicates which type of company a card is affiliated with, such as an airline, banking institution, or retailer.

The MII can also help identify which major card network the card belongs to: American Express (3), Visa (4), Mastercard (5), or Discover (6).

The first six digits of a credit card number, known as the Issuer Identification Number (IIN) or Bank Identification Number (BIN), indicate which credit card company a card comes from.

Here are some examples of IINs for the 10 largest U.S. credit card issuers:

The last number of the credit card number is a final check for payment processors, helping to protect the account from unauthorized use.

If you've lost or stolen your credit card, it's essential to report it to your bank immediately to prevent any unauthorized transactions.

Your credit card number is typically formatted with 16 digits, divided into four groups of four digits each, as seen in the example: 4532 1143 2211 1111.

You should contact your bank's customer service number, which is usually printed on the back of your credit card or on your bank's website.

The credit card issuer will likely ask for your account information, including your card number and expiration date, which is usually in the format of MM/YY.

Once reported, your bank will likely freeze your account to prevent any further transactions, and then issue you a new card with a new account number.