A stock-keeping unit, commonly abbreviated SKU and often pronounced "skew", is an internal alphanumeric code that a retailer or wholesaler assigns to a particular product variant. It identifies an item by attributes such as model, size, color, or packaging so staff and systems can track stock levels, pricing, and sales history. The term "SKU" itself stands for Stock-Keeping Unit.

Characteristics and format

  • SKUs are typically alphanumeric and structured to carry human-readable information (for example: category, style, color).
  • There is no single global standard for SKUs; each company designs its own scheme to match operational needs.
  • SKUs may be printed as text or encoded in barcodes so optical scanners can read them at point of sale or in a warehouse. See resources on barcode technology: barcode basics.
  • SKUs differ from universal product identifiers like UPC or GTIN, which are assigned by manufacturers; SKUs are retailer-specific.

Barcodes and automated scanning systems gained widespread use in retail during the late 20th century as a way to speed checkouts and reduce errors. Modern point-of-sale and inventory systems link a scanned code to the SKU record to retrieve price, stock status, and product details. For an overview of scanning hardware, consult scanner guides and device standards scanning technology.

Common uses of SKUs include inventory control, reorder and replenishment planning, sales analysis by variant, and online catalog management. E-commerce platforms and warehouse management systems rely on consistent SKU schemes to sync listings, manage returns, and route fulfillment. Businesses also use SKUs to track profitability at a variant level and to implement promotions or bundle offers: see typical implementations at inventory best practices.

Best practices for creating SKUs emphasize clarity and consistency: avoid ambiguous characters, keep codes a manageable length, and encode only stable attributes to reduce churn. Remember that SKUs are internal tools and can coexist with manufacturer barcodes; mapping between SKUs and external identifiers (UPC, EAN, ASIN or GTIN) is a common requirement when integrating suppliers or marketplaces. Additional technical and organizational guidance is available via integration references.