UPCA

UPCA, commonly written UPC-A, is a barcode symbology used to encode 12 numeric digits for retail products in North America. It is one of the formats within the Global Trade Item Number system (GTIN-12) and is maintained by GS1 (formerly the Uniform Code Council in the United States). The symbol enables automatic identification and price lookup at point of sale and is widely scanned by laser or imaging systems.

The UPC-A symbol consists of a left and a right half separated by a middle guard, with start and end guards to aid scanning. Each of the 12 digits is represented by seven modules of bars and spaces, giving a total of 95 modules overall (not counting the quiet zones on either side). The twelve digits encode a number system digit, a six-digit manufacturer code, a five-digit product code, and a check digit. The first digit determines the encoding pattern used on the left-hand six digits, while the right-hand six digits always use a fixed pattern. The final digit serves as a check digit, calculated from the preceding eleven digits using a weighted sum and modulo 10.

UPC-A is a subset of the broader EAN/GTIN system; an UPC-A code can be represented as an EAN-13 code by prefixing a leading zero. The format is widely used on consumer packaged goods in the United States and Canada and is commonly found under the price on product packaging. A related variant is UPC-E, a zero-suppressed version for small packages. The first UPC barcode was scanned in 1974 on a pack of Wrigley’s Juicy Fruit gum in a U.S. grocery store.