Direct answer. An SKU (Stock Keeping Unit) is the unique reference code that a company assigns internally to each precise variant of a product — color, size, packaging, batch — in order to track it individually in its WMS, its stock and its orders. Unlike a standardized barcode, an SKU is specific to the company that assigns it.
SKU, EAN/GTIN, consumer unit: don't confuse them
The SKU is often confused with the product's barcode, even though the two are distinct. The SKU is an internal reference, freely defined by each company according to its own naming scheme, used to distinguish two variants of the same product (for example, a single garment style available in three sizes generates three different SKUs). The EAN/GTIN, on the other hand, is a barcode standardized by the GS1 organization, identical regardless of the retailer, and shared among all commercial partners of a supply chain — manufacturer, warehouse, point of sale. A single SKU at one retailer can therefore correspond to one unique, universal EAN on the manufacturer's side.
The SKU is also distinct from the consumer sales unit (UVC): the UVC is the unit purchased by the customer, while the SKU is the management identifier used to track it in stock — a single product can have one SKU for its sales unit and another SKU for the carton that groups several of them. The more SKUs a warehouse manages (a larger catalog, a wide variety of references), the more strategic addressing and slotting become for keeping stock legible and picking efficient, and the more necessary cycle counting becomes for keeping the stock levels shown in the WMS reliable.
FAQ
What is the difference between an SKU and an EAN code?
The SKU is an internal management reference freely defined by each company to distinguish its product variants. The EAN (or GTIN) is a barcode standardized by GS1, identical for every player in the supply chain. Two companies can use different SKUs for the same product identified by a single EAN.
How many SKUs can a warehouse manage?
There is no universal ceiling: it depends on the sector, the available floor space and the WMS's level of automation. A general e-commerce warehouse can track tens of thousands of active SKUs, which makes dynamic addressing and slotting particularly important for keeping picking efficient.
Related terms
UVC / UM · Location addressing · Slotting · Cycle counting · Packing · Turnover rate.
See also: Euro pallet dimensions, pallets per truck.
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