Automating assigning a 12 digit UPC number

Hey everyone!

At my workplace, I am tasked with assigning GTIN-12 UPC numbers for new products. We have a spreadsheet to assign these numbers but once I get the 11-digit UPC I have to manually enter the 11-digit number into a check digit calculator.

Automating this process would save me tons of time.

I've not been able to find formulas that work in previous threads. Here's an example of what I've seen.

=CONCATENATE(A1,RIGHT(ROUNDDOWN((SUM(RIGHT(A1,1)+MID(A1,9,1)+MID(A1,7,1)+MID(A1,5,1)+MID(A1,3,1)+LEFT(A1,1))*3+SUM(MID(A1,10,1)+MID(A1,8,1)+MID(A1,6,1)+MID(A1,4,1)+MID(A1,2,1))),1)))

You can see the formula the GTIN-12 check digit calculator uses on the gs1 website.

Hopefully, someone can help me and others who have had this same issue.