From the right to left sum all digits in odd positions and multiply
the result by 3.
Sum all digits in even position.
Sum the results from the above two steps and do a MOD 10 on the total.
The check digit is the number which when added to the remainder equals
10.



On Fri, 18 May 2007 20:06:00 -0700, David
wrote:

Hi,

We are trying to figure out how to calculate the UPC check digits? Is there
a formula for this calculation? For an example, on cell A1 we enter
74758551488 then A2 will calculate the digit.

Greatly appreciate any helps on this in advance!