On Tuesday, April 9, 2013 10:21:02 PM UTC+23, wrote:
These formula's are great! One of the biggest problems I'm having is calculating the check digit for UPC-E 7 digits and UPC-E with leading 0's with would be 6 digits. Any recommendations?

Not following your question: are you trying to add 6 zeroes to the front of a 7 digit string?

Also, and this would be AMAZING, my biggest issue is check UPC-A's and UPC-E's for check digits to see if they are valid UPCs. I work with 100,000+ UPC items a day and it's really hard processing them because I have to determine which items contain check digits and which ones do not. I am willing to pay for a soluation!

In the OP's question he had a 12-digit number that required a check digit. Not following this part of the question either: if the number has a check digit it will be a certain length, and if it does not have a check it will be one character short, correct?