SKU

Stock-keeping unit (SKU) is a unique identifier used by retailers and warehouses to track a product and its variations within their own inventory management system. The term originated in retailing and inventory control and is distinct from universal product codes.

An SKU typically encodes product attributes such as category, brand, model, size, color, and packaging. The exact format is defined by the organization; SKUs can be numeric, alphabetic, or alphanumeric. They may be designed to be human-readable but many systems use opaque codes.

SKUs are used to organize stock, manage reorder processes, calculate inventory levels, and generate reporting. They enable tracking of stock-keeping by location, supplier, and fulfillment channel. They are often linked to other product data in a master database.

While SKUs are widely used, they are not universal identifiers. Global trade items are identified by UPC, EAN, or GTIN, which are standardized across retailers. An SKU may map to one or more barcodes, but the barcode is not the same as the SKU.

Best practices include developing a consistent SKU schema, documenting rules, avoiding gaps when variations are created, and ensuring SKUs remain stable when items change. Regular audits, de-duplication, and alignment with product data management help maintain accuracy.

Limitations: SKUs can proliferate with variations; poor naming can hamper readability, SKU drift occurs when attributes change without updating codes; changes may require system updates and historical data complexity.