Cracking The Credit Card Code

This handy infographic will tell you all about what the numbers on your credit card actually mean and how you can manually validate a credit card number with your mind.

[Source: MintLife]





12 Responses to Cracking The Credit Card Code

  1. This isn't entirely true. Debit cards will often fail the Luhn algorithm (Chase debit cards are notorious for this). The reason being that the bank licenses the use of the credit carrier's logo (i.e., Visa) from Visa. But the rest of the number is completely made up by an algorithm internal to the bank.

    Hence companies that only compare against the Luhn algorithm will fail some (but not all) debit cards.

    • Not to be finicky with the semantics, but…

      The example says it works for "credit" cards. Nowhere in that picture does the word "debit" or the phrase "debit card" even show up.

      • People frequently use the two interchangeably not realizing there's a difference. There are people that will try to decode their card with this information or try to get it to pass the Luhn and it won't work. Simply calling it out so they know why.

  2. Cards that start with 3 are issued by American Express. 4 are issued by Visa and 5 is MasterCard. I believe 6 is Discover Card.

  3. Btw, you don’t have the algorithm for the security code on the back of the card ? ;)

  4. the graphic says 2 completely different things about the first digit. first it says 3 means travel and entertainment, then it says 3 means american express, 4 means banking, 4 means visa, etc. how can the first digit mean two completely different things? there are visa cards issued by banks and by american airlines and whatever else.

    • VISA originated as a financial services credit card (Bank of America). American Express originally was a stage/railroad company, but their foray into financial services was the travelers cheque. As for VISAs coming from American Airlines, the card isn't issued by AA but by an issuing bank with AA's name on it. American Airlines' VISA is issued by Citibank, if their credit application is to be taken as primary evidence.

  5. I have tried this on all my credit cards and not one = a number divisable by 10. And they are all valid credit cards, so i call BS on that part of this. And they are not debt cards they are credit cards.

    • Weird. I tried it on 1 Discover, 2 Visa and 2 Mastercard credit cards and it worked for all of them. It also worked on a bank issued Visa debit card. Only thing it did not work on was a 14 digit Lowe's store credit card.