Glossary
SKU
Also called: Stock Keeping Unit
A SKU is your own code for one exact thing you sell, down to the size and colour. You invent it, and only your shop uses it.
That is the difference from a GTIN. A GTIN is registered and shared. A SKU is yours.
One SKU per variant
A blue medium hoodie and a blue large hoodie are two SKUs. If you can sell one without the other, count one without the other, or run out of one and not the other, it needs its own code.
Shopify has a SKU field on every variant for exactly this reason.
Building one that lasts
Good SKUs are short, readable out loud, and sorted by something useful:
- Start with a supplier or brand code, three letters
- Then a product code
- Then the variant, size and colour last
ACM-HOOD-BLU-M tells a person in the stockroom what it is. 10429 does not.
Leave gaps. If you number products 001, 002, 003 you will one day need something between two of them.
Where it goes wrong
Letters that look like numbers. O and 0, I and 1, S and 5. A
handwritten SKU on a bin location label gets read
back wrong, and the count goes on the wrong line. Pick one set, drop the other.
The other fault is reusing a retired SKU for a new product. Two years of sales history now belong to something else, and every report that touches it is wrong. Retire codes properly and let the old dead stock keep its number.
Related terms
GTIN
Also called: Global Trade Item Number
A GTIN is the number that identifies a product worldwide. The barcode on the box is just a way of printing it.
Bin location
Also called: Bin, Storage location
A bin location is the address of a place in your stockroom, so anyone can be told where to find a product without being shown.
Dead stock
Also called: Obsolete stock
Dead stock is inventory that is not selling and is not going to, tying up money and shelf space you need for something else.