Tool description

Ever wondered how websites know if you typed your credit card number correctly? That is where the Luhn algorithm comes in! This handy tool checks if a number follows the Luhn algorithm rules - a simple but clever way to catch typing mistakes.

Alternative algorithms

While Luhn is the most popular kid on the block for credit card numbers, there are other number checking methods out there. Some use more complex math (like Damm algorithm), while others are custom made for specific purposes. But Luhn keeps winning hearts because it's simple and catches the most common typos.