Luhn Algorithm Calculator

Luhn Check Digit Calculator

The Luhn algorithm is used to validate various identification numbers, such as the numbers on the front of credit cards, social security numbers or the IMEI of a phone.

The last number of a Luhn sequence is the control digit. If you enter a digit incorrectly, therefore the algorithm will calculate a different checksum. So, the Luhn algorithm is well suited for checking numbers entered by people. In case they have a typo in their sequence, then the last digit will fail the validation.

If you want to see the validation method, take a look at this answer.