# SKU

> 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.

- Source: https://storestandards.com/glossary/sku/
- Also called: Stock Keeping Unit
- Updated: 2026-08-14
- Author: Nia Chambers, Product, Store Standards

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That is the difference from a [GTIN](https://storestandards.com/glossary/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](https://storestandards.com/glossary/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](https://storestandards.com/glossary/dead-stock/) keep its number.

## Related terms

- [GTIN](https://storestandards.com/glossary/gtin/): A GTIN is the number that identifies a product worldwide. The barcode on the box is just a way of printing it.
- [Bin location](https://storestandards.com/glossary/bin-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](https://storestandards.com/glossary/dead-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.