What GS1 is and why it exists
GS1 is a nonprofit standards organization, with member organizations in over 100 countries, that maintains the numbering system behind the barcodes scanned at nearly every retail checkout. Its core purpose is ensuring a product identifier is globally unique no two products anywhere in the world share the same GTIN, so a scan at any store or warehouse resolves to exactly one item.
Without a shared standard, every retailer or distributor would need its own private numbering scheme, making it impossible to share product data or scan the same item consistently across supply chain partners.
What a GTIN is
A GTIN (Global Trade Item Number) is the unique number GS1 issues for a specific product. The barcode you see on packaging UPC-A (12 digits) in the US and Canada, EAN-13 (13 digits) internationally is simply that GTIN encoded as a scannable barcode.
A GTIN identifies a specific product at a specific packaging level: a single unit, a case of twelve, and a pallet of ten cases each typically need their own distinct GTIN, since they are different "trade items" even if they contain the same product.
How you get a GS1 company prefix
To generate your own GTINs, a business licenses a GS1 company prefix through its local GS1 member organization (GS1 US in the United States, for example) for an annual fee based on how many product numbers you expect to need. That prefix becomes the fixed leading digits of every GTIN you assign, with the remaining digits identifying each specific product.
Buying a "UPC code" from a third-party reseller instead of licensing directly from GS1 can create ownership and uniqueness problems some retailers and marketplaces require GS1-licensed prefixes specifically and reject numbers sourced elsewhere.
Other GS1 identifiers you may encounter
Beyond GTINs, GS1 standards include a GLN (Global Location Number) for identifying specific physical locations like warehouses or stores, and SSCC (Serial Shipping Container Code) for tracking individual pallets or shipments through logistics. Most small businesses only need to worry about GTINs for their products; GLNs and SSCCs typically become relevant once you work directly with large retail or logistics partners that require them.
GS1 standards vs. your internal SKU
GS1 registration only matters for products moving externally through retail or marketplace channels. Your internal SKU the identifier your own team uses to track inventory is entirely separate, can follow any format you choose, and needs no registration or license at all.
Most inventory software generates internal warehouse labels as Code 128 barcodes built from your SKU, while keeping the product's official GS1-issued UPC/EAN on the same item record for retail scanning. The two systems coexist: one for your operations, one for the outside world.
- GTIN/UPC/EAN GS1-issued, required for retail and marketplace sale
- Internal SKU your own format, no license needed, used for warehouse operations
Keep GS1 codes and internal SKUs in sync
StockFlow stores your product's official UPC/EAN alongside your internal SKU on the same item record, so retail scanning and warehouse operations never fall out of sync.
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