What The Numbers On Credit Cards Mean

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Have you ever had to type your credit card number into a mobile phone or computer form? If so, you have probably wondered why the number has to be so long. To answer this question, it might help to take a look at what each digit in a typical credit card number actually means.

Why Do Credit Card Numbers Have 16 Digits?

This 16-digit number was standardized in 1989 by international agreement. This standardization allows people to use many of their cards almost anywhere in the entire world.

This is a simple explanation of the digits:

  • First digit: The first number identifies the kind of company that issued the card. For example, banks and financial companies usually use 4 or 5. For a couple of common examples, MasterCard uses a 5 and Visa uses a 4.
  • Second through sixth digit: These numbers are unique identifiers for the card issuer. In some cases, issuers have different identifiers for various lines of business. As an example, your bank might use one number for credit cards and another number for debit cards.
  • Seventh through fifteenth digit: These digits are used to identify the person who holds the account, but it’s possible that the same person could have a different number for different accounts with the same company.
  • Sixteenth digit: This is a check digit that’s used to help verify that cards are entered correctly. It’s not used for security because the algorithm that calculates this digit has been published many times and was developed over 50 years ago.

How Do Credit Card Processors Prevent Entry Errors With Credit Cards?

Simple entry errors are very common with these long credit card numbers. It’s pretty easy to make a simple mistake when you have to key in a long credit card number. However, credit card processors usually have some checks in place to catch these before they go through.

For example, some cards also have a credit verification value, or CVV, on the back. This is a three-digit number that provides an extra check. Online transactions usually also require these. Most credit card processors also require the card’s expiration date, the card holder’s name, and the holder’s address to verify the number against.

These checks are mostly to guard against simple mistakes, and they aren’t intended to actually provide a high level of credit card security. It’s still very important for credit card holders and credit card issuers to monitor their accounts to make sure that they haven’t been used by thieves to commit credit card fraud.