The Amazon FNSKU Barcode Guide

What is an FNSKU?

FNSKU stands for **Fulfillment Network Stock Keeping Unit**. It is a unique identifier used by Amazon to track products specifically assigned to an individual seller. Unlike a UPC, which identifies a product type, an FNSKU identifies the specific unit as belonging to *your* inventory.

Structural Anatomy

Every FNSKU barcode follows a strict technical and visual standard:

• Symbology: Amazon strictly requires the use of the Code 128 linear symbology.
• Prefix: Almost all FNSKUs begin with the "X00" prefix, which indicates it is a seller-labeled item.
• Length: Typically 10 characters long, containing a mix of capital letters and digits.
• Quiet Zone: Amazon requires a significant blank space (Quiet Zone) on the left and right of the barcode to ensure scannability.

Labeling Requirements

Amazon FBA labels must be printed in black ink on white non-reflective paper with removable adhesive. Each label must also include the product's title and condition (e.g., "New") in human-readable text below the barcode.