What is a SKU? Using stock keeping units in eCommerce

Fulfilment Stock and Inventory
An example of a stock keeping unit (SKU), containing brand, product, size and colour

Heard someone say “es-kay-you” or “skew”? Not sure what a SKU is and if you need one? This is the post for you. We answer some of the frequently asked questions about stock keeping units, and show you how to use them to make your eCommerce business a success.

What does SKU stand for?

SKU stands for stock keeping unit. Some people pronounce SKU letter by letter – “an es-kay-you”. Others (like us) pronounce it as a single word – “a skew”

What is a SKU example?

In eCommerce, a SKU is a code that represents one, unique product line. It’s usually a combination of letters and numbers that reflect the characteristics of that product. So, to take the SKU example above:

  • JJF-TS-SML-GN would be a small, green, James and James Fulfilment t-shirt
  • JJF-TS-LRG-GN would be a large, green, James and James Fulfilment t-shirt
  • JJF-TS-SML-OR would be a small, orange, James and James Fulfilment t-shirt

Is a SKU the same as a barcode?

A SKU and a barcode are similar in that they both refer to one, unique product line.

Where they’re different is that a SKU can be read and understood by a human, without the need for a barcode scanner and related technology.

Also, if you resell products, you should refer to them using your own SKU, rather than relying on the manufacturer’s barcode. If you don’t, and the manufacturer changes the barcode later, you’ll need to update the SKU in multiple places – your online store, marketplaces, warehouse and so on.

Is a SKU the same as a serial number?

No. A SKU refers to one, unique product line. A serial number refers to one, unique product. So 100 small, green t-shirts would all have the same SKU number. But each one would have a different serial number, usually increasing in increments of one.

What format should a SKU number take?

Your SKUs should include any attributes that differentiate products from each other. So that could be brand, product, size and colour (as above), plus material, packaging, style and so on.

It’s also a good idea for the code to be extendable. For example, if your business does wholesale as well as direct-to-consumer sales, you’ll want SKUs for case sizes. A box of 50 small, green t-shirts might be:

  • JJF-TS-SML-GN-C50

Why should you use SKUs?

Using SKUs within your eCommerce business can have benefits in two key areas:

1. Pick and pack

A James and James team member takes items from a picking trolley at a packing desk
SKU numbers help our team members differentiate between similar products during the pick and pack process.

Labelling your products with both a SKU and a barcode can be really useful in a fulfilment warehouse during pick and pack.

For example, as our team travel around our fulfilment centres, picking items from the shelves and placing them on trolleys, they scan the items’ barcodes to check that they’ve selected the right ones.

When they bring these items back to a packing desk, to prepare them for despatch, there might be two or more similar items on one trolley, which need to go in different orders – for example, a black t-shirt and a dark grey t-shirt.

The SKU number helps them identify the right product quickly – something they couldn’t do with a barcode alone – ensuring that Mr X doesn’t end up with Mr Y’s dark grey t-shirt.

> Learn more about our pick and pack accuracy and efficiency

2. Inventory management

The second advantage of using SKUs is that it enables you to take more accurate stock readings, and understand your best and worst-selling products.

Without SKUs, you might know that you have 1,000 t-shirts in stock and some are selling well. With SKUs, you’ll know the exact size and colour breakdown, and that small, green t-shirts will sell out next week, unless you order more from your manufacturer now.

Having this sort of granular inventory management will ultimately save you money. It will reduce:

  • Capital investment required to buy new stock, some of which might already be unpopular with customers and unlikely to ever sell
  • Storage costs associated with maintaining a large range of products, some of which may be slow-moving
  • Missed opportunity costs, which come from running out of popular products, because you haven’t spotted they’re selling well and reordered.

> Learn how our order fulfilment software can help with your inventory management

How many SKUs should you have?

Now we know that SKUs are useful for managing your inventory, the natural question is how many you should have – just how big should your product range be?

Unfortunately, there’s no one-size-fits-all answer for this. It will depend on the industry you work in and the maturity of your business.

Established, clothing retailers will obviously have tens of thousands of SKUs, catering for different sizes and demographics.

Smaller, start-up retailers are likely to have fewer. Indeed, it’s sensible to begin with a handful of SKUs, and expand your range as your revenues grow and you get feedback from customers.

For example, our client, TAILORED ATHLETE, made a name for itself with muscle-fit shirts, before adding complementary products like jeans and polo shirts to its range.

> Find out how TAILORED ATHLETE improved its stock control with us

Want to know more about improving your pick and pack, and inventory management? Get in touch today for a free, no-obligation chat about how our order fulfilment services can help your business.