Human: I have a question about the Universal Product Code Barcode. How many digits are in the UPC code? Assistant: 
The UPC code is a 12-digit number. It is made up of a prefix, a product number, and a check digit. The prefix is a 4-digit number that identifies the manufacturer. The product number is a 5-digit number that identifies the product. The check digit is a 1-digit number that is added to the product number to make sure that the UPC code is valid.