What is a SKU? SKU Meaning for Online Retailers

A SKU is a stock keeping unit code your store creates to identify each item or variant it sells. SKU meaning is the same in retail, sales and warehouse work: the code connects the product to its stock record.

If you’re loading your first range into Shopify, you can create your own codes for the empty SKU fields. Give each size and colour combination its own code, then keep that code consistent wherever you manage the item.

SKU Meaning in Plain Terms

SKU stands for stock keeping unit. In a product record, the SKU is the internal code your business uses to identify the item. A product name describes it to a customer, while the SKU lets your team find the exact stock record.

A SKU number can contain letters as well as digits. For example, CSH482NT45 can identify a particular cushion in your range. The word “number” doesn’t mean you must use digits alone.

SKU meaning in business and SKU meaning in sales are the same. Your stock team counts units against the code, while a sales report groups transactions against it. A SKU identifies a product variant, not an individual customer order.

SKU Meaning in Retail and Warehouses

In retail, a SKU separates stock that customers can choose as different variants. One T-shirt in three sizes and two colours makes six SKUs, assuming you sell every combination.

For a hypothetical range with small, medium and large sizes in navy and white, each size has two stock records. Selling a small navy shirt reduces the small navy quantity. It leaves the large navy quantity unchanged.

The same rule applies to homewares. A natural linen cushion in two sizes needs a separate SKU for each size. The guide to product attributes explains which colour and measurements to keep beside the code.

A warehouse or third-party logistics provider (3PL) uses the SKU on a pick list to locate the right item. Staff count that item against its stock record and use its remaining quantity to decide when to reorder. The shelf location can change while the SKU stays the same.

SKU-level reporting shows results for each code separately. It can reveal that small navy shirts sell faster than large white shirts, even when a product-level report combines both. Six SKUs describe six variants, regardless of how many units you hold.

SKU vs Barcode, GTIN and MPN

A SKU is your store’s code, while a global trade item number (GTIN) is a shared product identifier allocated through the GS1 system. A barcode is the scannable symbol that can encode a GTIN or an internal code, and a manufacturer part number (MPN) is set by the manufacturer.

Identifier	Who assigns it	What it identifies	Usual use
SKU	Your store	Your item or variant	Stock records and fulfilment
GTIN	The product’s responsible company using GS1 identifiers	A trade item across businesses	Retail barcodes and product matching
MPN	The manufacturer	A product in the manufacturer’s range	Supplier and marketplace identification

Google Merchant Center requires a unique product id and recommends your SKU for that field. Its separate product-identifier fields use GTIN, brand and MPN according to the product’s identifiers. For manufactured products, copy the supplied identifiers into the correct fields. An invented store code cannot replace a missing manufacturer identifier.

Google’s own-manufacturer exception allows you to assign an MPN when you make and solely sell a product that has none. The Google product-identifier guidance explains that condition.

Marketplace requirements also depend on the listing. For example, eBay requires accurate brand and product identifiers where those fields are mandatory. A seller SKU remains your stock reference, even when you submit it to a marketplace.

Read the GTIN guide for barcode identification or the manufacturer part number guide for supplier codes. Keep each identifier in its own field.

How to Create SKU Codes

Build SKU codes from a category segment, a product segment and a variant segment. Give each segment a defined length so your team can read the code without spaces or punctuation.

This hypothetical Australian homewares range uses CSH for cushions and 482 for one linen cushion design. Its variant segment combines a colour abbreviation with the square cushion size in centimetres.

SKU	Category and product	Colour segment	Size segment
CSH482NT45	Linen cushion design 482	NT for natural	45 for 45 by 45 cm
CSH482GY45	Linen cushion design 482	GY for grey	45 for 45 by 45 cm
CSH482NT55	Linen cushion design 482	NT for natural	55 for 55 by 55 cm

To build your first master list, follow these steps.

1. List every sellable variant. Give the natural 45 cm cushion its own row, separate from the grey version.
2. Choose fixed abbreviations and segment lengths. Record that NT always means natural, so another team member can create the next code correctly.
3. Assign one unique code to each row. Use letters and digits only, without spaces or special characters.
4. Avoid confusing characters such as the letter O and digit 0, or the letter I and digit 1. Keep your chosen case consistent.
5. Check for duplicate codes before importing the list. Keep retired codes reserved so you never assign them to a different item.

Before loading the whole range, read a sample code back into its category and variant details. CSH482GY45 must lead to the grey 45 cm cushion and no other stock item.

Where to Find the SKU Number on a Product

Look for a field labelled SKU in the product details or seller’s inventory record. A product page can display it near the item specifications, but stores choose whether to show it publicly.

Printed documents can also carry the SKU. On a packing slip, it can sit beside the item and quantity to guide picking. An invoice can include it on the item line, and a shelf label can pair it with the product name. A number under a barcode isn’t automatically the store’s SKU.

In Shopify’s desktop admin, open Products and choose the product. For a product with variants, select the variant and find SKU in its Inventory section. Shopify’s Help Center says SKUs are optional, though an inventory or fulfilment integration can require them.

Etsy’s listing editor keeps the SKU field under Inventory and pricing. For separate variant codes, add or manage a variation under Item options and enable the option to vary SKU numbers. Etsy uses these seller-created codes to help you find and manage stock, including through listing search in Shop Manager.

If a shopper needs the code and the public page doesn’t show it, the retailer can look it up in the product record. A customer-facing product name alone might cover several variants.

Keeping SKUs Consistent Across Systems

Keep one master SKU list and use its codes in your store, inventory system and product feed. When systems match records by SKU, a mismatch can leave a sale disconnected from the correct stock record.

For example, your store might sell CSH482NT45 while the inventory system expects CSH482NT55. The wrong size can lose stock, or the update can fail because the code is missing. A product feed can then publish an outdated quantity.

Some integrations match on platform IDs instead. In that case, keep an explicit mapping from those IDs to your master SKU. Copying the same SKU into two systems doesn’t itself create a stock connection.

Rename a product without changing its SKU when the underlying item stays the same. If you discontinue it, mark the master-list row as retired and retain the code for historical orders and returns. Assign a new code to a genuinely different item.

Google also requires stable product IDs and prohibits recycling them for new products. If your feed uses the SKU as its ID, preserve that value when the product name changes.

Before importing your first 200 products, compare one variant across the master list and each connected system. Confirm that its code points to the same colour and size, then check that a stock update reaches that record.