FNSKU vs UPC: Which Barcode Does Amazon Need?
Amazon sellers often run into this question because UPC and FNSKU solve different problems. UPC identifies the product in a retail context. FNSKU identifies seller-specific inventory inside Amazon's fulfillment system.
Short answer: Amazon may require FNSKU on fulfillment units even when the product itself also has a UPC. UPC is typically the product barcode for retail and listing identification. FNSKU is Amazon's seller-specific inventory label.
| Feature | UPC | FNSKU |
|---|---|---|
| Main role | Retail product identification | Amazon seller inventory identification |
| Where used | Packaging, retail, product catalog systems | Amazon fulfillment prep and unit labeling |
| Who needs it | Brands and product packaging workflows | Sellers sending units through Amazon workflows |
| Typical output | Printed on product packaging | Printed on seller-applied unit labels |
What UPC is
A UPC is the barcode commonly used to identify a retail product. It is the barcode you often see on product packaging, retail listings, and consumer goods moving through standard retail channels.
What FNSKU is
An FNSKU is Amazon's barcode for identifying seller-specific inventory. It helps Amazon separate one seller's units from another inside fulfillment operations.
When Amazon requires FNSKU
Amazon can require FNSKU labels when fulfillment units need Amazon-specific identification for prep, receiving, and inventory handling. In those cases, the seller-applied FNSKU label becomes part of the shipment-prep workflow rather than replacing all broader product ID needs.
When UPC is still needed
UPC may still matter for product packaging, listing creation, or the broader retail product identity even if Amazon fulfillment units also use FNSKU. Think of UPC as the product code and FNSKU as the Amazon inventory handling code.
Fulfillment and labeling differences
If you are printing seller unit labels, Barcode Labels can help you preview sheet layouts before export. If you need many individual barcode files for operations or packaging prep, you may prefer the bulk workflow. For plan details around those advanced outputs, use Pricing.
FAQ
What is the difference between FNSKU and UPC?
UPC identifies the retail product itself, while FNSKU identifies seller-specific inventory inside Amazon fulfillment workflows.
When does Amazon require FNSKU labels?
Amazon requires FNSKU labels when seller inventory needs Amazon-specific identification for fulfillment prep and handling.
Do I still need a UPC if I use FNSKU?
Often yes. UPC can still matter for product identification and listing setup even when the fulfillment unit also uses FNSKU.