Found a Formula in a Spreadsheet Passed on to Me and Have No Idea What It's Supposed to Do

[tsgnms]

Hi all,

Sorry if this is posted in the wrong place, please let me know if it is and I'll repost elsewhere.

We have a barcode calculator which was passed on to me to use when I took on responsibility for generating them.

In cell C6 of the worksheet there are the bulk of the digits that make up the barcode, and we simply add 1 to this for each new barcode we create. For the final digit, a formula has been created years ago by someone to calculate the final digit in the barcode.

I'm assuming it's my untrained eye, but I cannot make sense of the formula or why they use this to calculate barcodes, so I'm hoping someone can decipher it for me. If it turns out to be a necessary thing, then I'll keep it as is but at least I'll know what it does. If not, I plan to simplify the calculator. The formula is as follows:

=C6&(ROUNDUP(((MID(C6,2,1)+MID(C6,4,1)
+MID(C6,6,1)+MID(C6,8,1)+MID(C6,10,1)+MID(C6,12,1))*3)
+(MID(C6,1,1)+MID(C6,3,1)+MID(C6,5,1)+MID(C6,7,1)
+MID(C6,9,1)+MID(C6,11,1)),-1)-(((MID(C6,2,1)+MID(C6,4,1)
+MID(C6,6,1)+MID(C6,8,1)+MID(C6,10,1)+MID(C6,12,1))*3)
+(MID(C6,1,1)+MID(C6,3,1)+MID(C6,5,1)+MID(C6,7,1)
+MID(C6,9,1)+MID(C6,11,1))))

Can anyone help shed some light on what this is supposed to achieve?

Thank you!

 

[Eric W]

I don't know much about bar codes, but that looks to be a check digit calculator. Whenever there's a long number, such as a credit card number, there typically is a check digit calculated for the last digit. This is to prevent single-digit typos essentially. It looks like that's the same thing adapted for bar codes. My guess is that you need to keep it.