SKU

How SKUs work

A SKU is the level at which you count, reserve, pick and report stock. A product is the idea (a linen bath towel); a SKU is one sellable version of it. If the towel comes in white, gray and sand, in two sizes, you have one product and six SKUs, such as TWL-WHT-L and TWL-GRY-M.

Every stock record, order line and count refers to a SKU. When an order asks for two large white towels, the warehouse looks up TWL-WHT-L, finds which locations hold it, and picks from there. If two versions share a SKU, nobody can tell them apart in the data, and the wrong one ships.

How to structure a SKU code

SKU codes are internal, so you choose the format. A few rules keep them readable on a pick list and hard to mistype.

• Keep them short, ideally under 12 characters, with fixed segments separated by a hyphen.
• Start with a category or product prefix, then the attributes that make the variant unique (color, size, pack).
• Avoid characters that are easy to confuse, such as O and 0 or I and 1.
• Don't encode things that change, such as price, supplier or storage location.
• Never reuse a retired SKU for a different item; old orders and reports still point at it.

SKU vs barcode vs GTIN

A SKU is your own code. A GTIN is a globally unique number issued under the GS1 system, and a barcode is just a way of printing a number so a scanner can read it. One SKU can have several barcodes: the retail barcode on each unit, a different one on the case, and your own label on a pallet.

The link between them is the pack structure. A case of 12 towels is still the SKU TWL-WHT-L, counted as 12 of the base unit of measure, even though the case barcode is different from the unit barcode.

Common SKU mistakes

Most SKU problems come from pushing too much information into the code.

• Creating a new SKU for each batch or expiry date. That belongs in lot tracking, not in the item code.
• Creating separate SKUs for the same item bought from two suppliers. Map each supplier's code to one SKU instead.
• Letting sales channels invent their own codes, so the same towel exists three times in the catalog.
• Building codes so long that pickers read them wrong.

How NextStock handles SKUs

In NextStock, a product has variants and each variant is a SKU. Each SKU can carry a pack hierarchy (each, case, pallet) with its own barcode per pack. Supplier SKUs live in the supplier catalog, and customer item codes map a customer's own part number to your SKU, so neither creates duplicates. You can load a full catalog through bulk import with validation and a preview before anything is committed.