Sometimes our customers ask us “What’s the difference between a SKU, MPN, and UPC?”. Here’s a brief overview of each, I tried to keep it as simple as possible:
UPC (Universal Product Code) is the standard for general products and is used by almost all barcode systems. Although, for books ISBN is more often used in addition. Amazon also its own system called ASIN (Amazon Standard Identification Number), although it’s not prevalent outside of Amazon.
SKU (Stock-keeping Unit) is another identifier that is often used, however, it is generally not universal for a particular product. For instance, each vendor for a particular product may assign its own SKU to that product. On the other hand, a product may have a MPN (Manufacturer Part Number, or a model number) that is assigned by the manufacture. While this number is unique, it is not very universal because each manufacturer uses it’s own numbering conventions.
So in summary, I’d say UPC is the most universal system. If you’re wondering how UPC numbers are unique, here is how it works:
UPCs originate with a company called the Uniform Code Council (UCC). A manufacturer applies to the UCC for permission to enter the UPC system. The manufacturer pays an annual fee for the privilege. In return, the UCC issues the manufacturer a six-digit Manufacturer identification number and provides guidelines on how to use it. You can see the manufacturer identification number in any standard 12-digit UPC code.
(Source https://hublogix.com)