Luhn check digit formula

[annnwy1]

Hey guys i need some help with Luhn check digit formula, i need to make formula for 13 and 14 digits for card number validation, i tried and i search online but it won't help... If someone knows or have the formula please help, it would be much appreciated!!

 

[Macropod]

Hey guys i need some help with Luhn check digit formula, i need to make formula for 13 and 14 digits for card number validation, i tried and i search online but it won't helpappreciated!!

I have to wonder what parameters you used to search here for previous threads on this. A simple search for Luhn returns 24 threads. See, for example: https://www.mrexcel.com/forum/excel...hin-excel-build-algorithm.html?highlight=Luhn