What is a SKU?

A SKU belongs to your shop. You choose it, and no other shop uses the same code for the same thing. A barcode belongs to the product and is printed by the manufacturer, so the same bottle of juice carries the same barcode in every shop that sells it. Many small shops need only one of the two. Shops that sell loose or repacked goods, or make up their own bundles, often need their own SKUs because no barcode exists.

A shop sells coconut oil in three sizes. Without codes, the stock sheet says only 'coconut oil', and nobody knows which size ran out. With a simple pattern of product, then size, the sheet reads:

Now the shopkeeper can see at a glance that the 1 litre bottle is the one to reorder, and a new cashier cannot sell the wrong size by mistake.

• Keep it short. Four to eight characters is easy to read and write on a shelf label.
• Make it readable. Start with letters for the product or category, then the size or type.
• Never reuse a code. If you stop selling a product, retire its code instead of giving it to something new, or old sales will point at the wrong item.
• Do not put prices in it. Prices change, codes should not.

The most common mistake is changing codes halfway through, which breaks your history. Pick a pattern, write it down, and stick to it. The guide on naming and organising products covers this in more detail.

Shopkeepa finds products by name and by barcode scan, and each product can also carry an optional SKU if you already use your own codes. Clear, consistent product names do most of the work a code would do. Naming each size as its own product, such as 'Coconut oil 500 ml', keeps counts and sales separate.