It is possible to read Universal Product Code barcodes using a barcode scanner that is attached to an appropriate barcode database system. In addition to purpose-built scanners, many smart phones can read UPC barcodes using an appropriate app. Finally, it is also possible to manually read UPC barcodes using the numerals printed at the bottom of the barcode if the appropriate reference for the barcode is available.
The majority of UPC barcodes are patterned after the UPC-A standard that defines four basic parts to each code. The first number on the left of the barcode indicates the type of a barcode, such as a zero for most standard product codes, a five assigned to coupons or a three assigned to some drug-related codes. The second group of five numbers indicates the code assigned to the manufacturer of the product that has a given UPC code while the next six numbers indicate the product number itself.
The final number is a check digit that is used by automated scanners to confirm that they have correctly read the barcode, as it must be a product of all the other numbers in the barcode. Other formats used for some UPC barcodes include the UPC-E, UPC 2-Digit Supplement and UPC 5-Digit Supplement codes.