A UPC is a Unique Product Code. These codes are used by GS1, also known as Global Standards, to track and maintain a global standard of labeling and information communication standards. That’s a wordy way of saying that they make sure everyone is on the same page when it comes to identifying their products.
A UPC code will typically have 12 digits, and the last number of the UPC is the check digit. GS1 has a check digit calculator. If you add two digits to a UPC it becomes the product’s GTIN or Global Trade Identification Number. This number also serves as an identifying number. A GTIN with leading zeroes represents a single product since it is just the UPC with two leading zeroes. However, if the first two digits are non-zero on a GTIN then that is the code for a case pack of the product where the UPC can be found in the GTIN.
For example,
The UPC might be 818767311347 which is the UPC for the unique product.
Then the GTIN for a single product mentioned above would be 00818767311347.
And a case pack of that same item would be 10818767311348 because the first digit is non-zero representing it is not the GTIN version of the UPC code. Keep in mind that a GTIN will also have a check digit is its final digit.
Now you may wonder how you can get your own UPC prefix. Well, you can go over to GS1 and purchase the number of barcodes you think you will need. Get Your UPC Barcodes from GS1 US
Last, to answer your question of how they are used by Amazon…
They are used to verify that the item actually exists. This has stopped me in the past from “dry testing” products to see if there is demand because I don’t want to create a UPC code for a product that consumers don’t want.
On Amazon’s end, this is great though, and it is a step towards keeping their marketplace clean with verifiable products that actually exist and can be looked up on GS1.
