Credit Card Validator

Validate a credit card number for all of the popular credit card companies using two different popular methods. First is the Luhn Algorithm that gets the proper checksum for the card, the second method is the Bin Number Checker.

BIN Number Info

The first six digit number on a bank card is know as the Bank Identification Number (BIN) which identifies the location of the bank that issued the card, while the latter portion identifies the specific name of the bank. BINs are traditionally used by online Merchants as a way to detect fraud by matching the geographic area where the cardholder is located to the geographic area identified in the Bank Identification Number. The term Issuer Identification Number (IIN) and Interbank Card Association Number (ICA) also refer to this same collection of numbers.

Luhn's Proof

Interactive example of how we did the validation above using Luhn formula.

The check digit (x) is obtained by computing the sum of digits then computing 9 times that value modulo 10 (so that is: (70 * 9 mod 10)).

In summary:

1. Compute the sum of the digits (70).
2. Multiply by 9 (630).
3. Take the last digit (0).
4. The result is your check digit.

Significance of First Digit

The left most digit on the card has a lot more meaning than what you may think. The table below outlines what the number means in the larger scheme of things.

Credit Card Break Down by Issuer

Each card company is allotted a set number of prefixes they are allowed to use to generate their card numbers. You can think of these prefixes as being similar to area codes within a phone number. Each area code can tell you the state or province based on the first three digits of a ten digit phone number. The same can be done with the credit card prefix.