What Is an FNSKU and How Do You Create One?
An FNSKU is the barcode that ties each unit to your Amazon seller account. Here is what it is, how to create one, and the labeling mistakes to avoid.
2026-08-01
What an FNSKU is
FNSKU stands for Fulfillment Network Stock Keeping Unit. It is the unique barcode Amazon uses to identify a specific unit and tie it to your seller account, which is different from an ASIN (the product listing ID) or a manufacturer UPC. Inside a fulfillment center, the FNSKU is how Amazon knows the unit is yours.
How to create and print it
You generate FNSKU labels in Seller Central when you set up an FBA shipment: choose to have Amazon label or do it yourself, then print the labels and apply one scannable code per unit. Getting this right is a core part of Amazon FBA prep, where each label is printed clean and any existing barcode is covered.
Common FNSKU mistakes
The usual errors are unscannable or low-contrast labels, applying the wrong FNSKU, or leaving an old barcode visible so two codes scan on one unit. Any of these can get a shipment flagged. Our FBA prep mistakes guide walks through how to avoid them.
Let prep handle labeling
If you sell cross-border or at volume, having a prep partner apply FNSKU labels removes a whole category of rejected-shipment risk. To hand off labeling and prep, contact us.
FAQ
What is the difference between an FNSKU and an ASIN?
An ASIN identifies a product listing on Amazon, while an FNSKU identifies a specific physical unit and ties it to your seller account for FBA. One ASIN can map to your unique FNSKU.
Can I ship to FBA without an FNSKU label?
Not for standard FBA. Units need the correct FNSKU label (or Amazon barcode) applied before they arrive, otherwise the shipment can be delayed or refused.
Who should print and apply the label?
You can, or Amazon can for a fee, or a prep partner can apply it to spec as part of prep, which is the safest option at volume.