Websites · Glossary
What is a SKU?
A SKU, short for stock keeping unit, is a code a seller assigns to each distinct product they stock, down to each size and colour, such as APR-OAT-L for a large oat linen apron. It identifies exactly what to pick, count and reorder. Unlike a barcode, a SKU is your own internal code, so you choose the format.
SKUs are small, but they save time in every part of selling: packing the right item, counting stock, reading sales reports and moving between systems.
Nuwan Madhusanka · Co-founder
3 min read · Published
SKU versus barcode
A barcode number such as a GTIN identifies a product globally and comes from a registered system, the same for every shop selling it. A SKU is internal: two shops selling the same mug give it different SKUs. Small makers often have SKUs but no barcodes, which is fine for selling on their own site.
What a good SKU looks like
Short, unique, readable and built from the attributes that matter: product, then variant details. APR-OAT-L reads as apron, oat, large. Avoid spaces and characters that confuse spreadsheets, avoid starting with zeros, and never reuse an old SKU for a different product.
Where SKUs earn their keep
On the packing bench, where a printed SKU tells you which shelf; in stock counts, where codes are faster than descriptions; in reports, where sales group cleanly; and when importing or exporting products, where a SKU keeps each variant matched as titles and photos change.
Common mistakes
Using the product title as the SKU, so a renamed product breaks records. Encoding prices or dates into SKUs that then go stale. Giving every variant the same SKU. And making codes so long that nobody types or reads them correctly.
Where it shows up in OneCraft
Each product variant in the store has an optional SKU field beside its price, compare at price and stock. The CSV import reads SKU columns from Shopify, WooCommerce, Square and plain sheets, and orders keep the item details for packing. A SKU is up to 64 characters in the variant table.
Questions people ask
Do I need SKUs for a small online shop?
Not strictly; a shop with a few products can run without them. They become useful once you have variants, stock to count or plans to move platforms, so adding them from the start is cheap insurance. Leave the field empty if a product truly does not need one.
Is a SKU the same as a product ID?
No. A product ID is usually assigned by the platform and may change if you move systems. A SKU is chosen by you and stays the same wherever you sell, which is why imports and exports rely on SKUs to match variants between platforms.
Should each size and colour have its own SKU?
Yes. Each combination you stock and count separately should have its own SKU, because it is a different thing to pick and reorder. A product in three colours and two sizes has six variants and therefore six SKUs, each with its own stock count.
Can two products share a SKU?
They should not. A SKU exists to identify one stocked item precisely, and sharing breaks stock counts and order picking. If two listings sell the same physical item, consider making them one product with variants instead, so the stock count lives in one place and cannot drift.
How long should a SKU be?
Long enough to be unique and readable, short enough to type and print, often 6 to 12 characters. Platforms set their own maximums, commonly far above what is practical. If staff cannot read a SKU aloud easily, it is probably too long.
Make one with websites
The button opens the generator with this use case already described. Change the wording to match your own.
Create a website with OneCraftRelated questions
- What are product variants?What are product variants? The buyable versions of a product made from its options, like size and colour, each with its own price, SKU and stock, with examples.
- What is a compare at price?What is a compare at price? The original price shown crossed out next to a lower sale price. How it displays and the law on was and now pricing.
- What is a collection in ecommerce?What is a collection in ecommerce? A group of products shown together, like New arrivals or Mugs, with its own page, and how they differ from categories.
Written and checked by the OneCraft team. Last checked .