What is a SKU

What actually is a SKU?

The SKU is not, as is often misunderstood, the inventory of an item, but rather something like an item number. However, the SKU offers more flexibility than an article number because it can contain any character string.

The acronym “SKU” is probably not very familiar to retailers outside the US. I know from conversations with customers that the term is often misunderstood. Because the SKU is not, as is often assumed, the stock of the product, but a unique character string that identifies the product.

Stock keeping unit

The written SKU is called “Stock Keeping Unit”. The last term “unit” could lead one to believe that the SKU is any unit. And when you think of “unit” you somehow automatically think of “number”, right?

The SKU is by no means an item's inventory in Shopify (and elsewhere). This is specified separately in Shopify for each variant in the "Quantity" field. The SKU is best to be translated as "Article number", in the sense of a unique number or character string that identifies the respective product in exactly one variant.

However, an SKU is much more flexible in its design than a plain article number. Because the latter actually only consists of a long sequence of digits, while the former may also contain letters and therefore is or can be much more “speaking”.

257305673284 or RETROSHIRTROSAXXL?

The SKU for a pink "retro" shirt in size XXL could e.g. RETRO SHIRT ROSEXXL while the article number would be just 257305673284. Both are clear, but there is probably no doubt which nomenclature is more descriptive.

Anyone who has ever gone a little deeper into the subject of computer-aided databases may have heard the term “matchcode”. This is a key composed of various fragments of the data in a data record which - ideally - uniquely identifies the respective data record. In theory, a matchcode is not necessarily unique, but the probability that a matchcode is ambiguous within a database table is relatively low.

A SKU is to a certain extent like a matchcode, in the sense that it is a date composed of fragments of the data of a product - product name, color, size, etc. - that uniquely identifies a variant of a product.


In order to use the SKU correctly, you only have to remember the following: Assign a character string that is unique and (at least for you) legible for all items in the entire shop as the SKU.

Never miss an article again! Subscribe to the ShopStack blog:

Subscribe via RSS