Credit card issuers first assign the account numbers and then compute steps one through three of the Luhn algorithm to determine the appropriate check digit. In this case, the card number should ...

The Luhn algorithm—also known as the “Modulus 10 algorithm”—is a formula used to determine the accuracy of credit card numbers.

All mainstream credit card numbers obey a mathematical trick designed to catch the most common typos. It’s called the Luhn ...

That long number isn't random, and it identifies more than just whose account the card belongs to. Many or all of the products on this page are from partners who compensate us when you click to or ...