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Commerce marketingReviewed September 7, 2026

What is SKU?

A SKU is a merchant-defined internal identifier used to distinguish and manage a product or variant in its own catalog.

Who this applies to#

  • Assign SKUs at the product or variant level needed for internal inventory and fulfilment work

What SKU requires#

  • Keep each active SKU unique inside the merchant's own operating system
Shopify

Shopify provides a SKU field on product variants for internal tracking

What this does not require#

  • A SKU does not have to be a globally standardized identifier issued by GS1

Common mistakes#

  1. Using SKU and UPC interchangeably
  2. Reusing one SKU for variants that need separate stock

SKU checklist#

  • Choose a stable format
  • Assign at the right variant level
  • Keep it unique
  • Do not encode facts that change often

Commonly confused with#

Official sources#