SKU (Stock Keeping Unit)

Short for stock keeping unit, SKU is a unique numerical identifying number that refers to a specific stock item in a retailer’s inventory or product catalog. The SKU is often used to identify the product, product size or type, and the manufacturer. In the retail industry, the SKU is a part of the backend inventory control system and enables a retailer to track a product in their inventory that may be in warehouses or in retail outlets.

Are SKU and serial number the same?

No. While SKUs and serial numbers may look similar, they have separate goals. SKUs are used in context of inventory before an item is sold, and serial numbers are used in context of ownership. Serial numbers help verify warranty eligibility if something breaks with a software or piece of equipment and can aid in recovering items that have been stolen or lost. Further, multiples of the same item will have the same SKU but unique serial numbers.

What is the difference between SKU, PLU, and UPC?

Unlike SKUs and serial numbers, the differences among PLUs (price look up), UPCs (universal product code), and SKUs are less clear. All three categories of codes are combinations of numbers that identify something about a specific item, and sometimes those identities overlap for simplicity or efficiency.

UPC codes are put in place by the manufacturer and identify the same product at different stores. SKUs are put in place by the retailer, though, so sometimes the SKU will be different if the manufacturer has changed the UPC for an item after it has been distributed to retail stores. For this reason, most UPC and SKU codes will be the same, but sometimes they will be different depending on the store and the item itself.

A PLU is used for produce items that are sold by weight, volume, or quantity. These global codes are typically shorter only 4 or 5 digits and are assigned by the International Federation for Produce Standards (IFPS). Grocery stores may or may not use the PLU as the SKU for an item, but in general PLUs are used to make POS transactions and inventory updates easier and faster.

Vangie Beal
Vangie Beal is a freelance business and technology writer covering Internet technologies and online business since the late '90s.

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