If you have observed your credit card number it may seem like a random string of 16 digits. Today I will show you how to make sense of these numbers and what all information is encoded in these numbers.
First digit of the card number discloses the category of industry. For e.g American Express credit card numbers begin with 3, Visa/Master card begin with 4 or 5. Read more about credit card industry categories here.
The first six digits verify the financial institution which issued the credit card like:
Mastercard: 51xxxx – 55xxxx
Discover: 6011xx, 644xxx, 65xxxx
Amex: 34xxxx, 37xxxx
Digits beginning 7th through the last but one identifies a person’s account number and the last number is checksum or the check digit and is used to validate the card number using the Luhn algorithm.
You can verify if a given credit card number is valid or not by using simple additions. See the following infographic from Mint.com which demonstrates how easy it is to validate a given credit card number.
Let me know what do you think about this.