In one sentence
A SKU, short for stock keeping unit, is the unique code a store gives each product variant, like one shirt in one size and color, so it can track inventory and orders without mix-ups.
How SKUs work for online stores
Every variant you sell gets its own SKU. A t-shirt in three colors and four sizes is one product with twelve SKUs.
You create SKUs yourself, so they can follow any pattern. A readable one packs in the details: TEE-BLK-M for a black medium tee. Keep them short, use letters and numbers only, and never reuse a retired code.
SKU vs. UPC vs. GTIN: what's the difference
Why SKUs matter for ecommerce operations
Clean SKUs keep inventory counts, warehouse picks and returns accurate. When you sell on more than one channel, or ship through a third-party logistics (3PL), the SKU is how every system knows it's talking about the same item.
For shopping channels and AI, pair each SKU with a GTIN in your product feed, so outside systems can match your product to the same item elsewhere.
About the author
Jenn Starr, Co-founder, Selix
Jenn has spent 20+ years helping SaaS startups build their marketing and implementation playbooks. She has bootstrapped three marketing agencies and is a 500 Startups alum. At Selix, she leads the work of getting ecommerce brands named in AI answers.
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