Press Space Enter Credit Card Number (all digits, no spaces, letters or punctuation) Hit Enter See Results!
This uses the Luhn Formula, named after its inventor Hans Peter Luhn. It works by multiplying every other digit by 2, adding the digits together (if multiplying makes it a two digit number) and then adding all the digits together. If the result is divisible by 10, it's valid! More Info: https://www.creditcards.com/credit-card-news/luhn-formula-credit-card-number-system-1273.php https://www.creditcards.com/credit-card-news/assets/Luhn.pdf https://en.wikipedia.org/wiki/Luhn_algorithm
