IMEI is a 15 digit long number where the 15th digit is a check digit which is calculated by applying LUHN algorithm to the first 14 digits.This app helps in calculating the Check digit if you type first 14 digits of the IMEI.This app would be helpful to testers who want to create a valid IMEI for testing by entering 14 digits or if you have 14 digits of the IMEI and want to know the 15th digit to get a valid IMEI.This tool is generally used by testers to generate multiple test IMEIs for different devices for mobile buyback applications.