Find the single digit at the far right lower corner of the bar code. This so-called check number is derived by applying a complex formula to the 11 previous digits.

UPC barcodes are a 12-digit UPCA or a 6-digit UPCE code. UPCA codes are used on standard size labels or packages. UPCE codes are a condensed version of a UPCA code, used when the size of a package ...

Universal product codes -- UPCs -- are the 12-digit numbers that appear under the barcodes on many U.S. products. They are given out by GS1 US, a nonprofit group that sets standards for ...

UPC bar code has been in use 30 years / Once-controversial technology is now ubiquitous. By Tricia Bishop, Baltimore Sun July 5, 2004. It was met with more criticism than even Michael Moore could ...

See UPC code example above right. That means a bottler would have to shut down the bottling line, and insert a new label, just for New York.