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Mastering Amazon FNSKU labels and barcodes for FBA sellers: The Definitive Guide

Updated: Oct 25, 2023

Mastering Amazon FNSKU labels and barcodes for FBA sellers: The Definitive Guide for Efficient Inventory Management

The e-commerce landscape, largely dominated by giants like Amazon, has drastically transformed the way businesses operate. For those leveraging Amazon's Fulfillment by Amazon (FBA) service, understanding the role and usage of Fulfillment Network Stock Keeping Units (FNSKUs) is integral. This guide will unpack the importance of FNSKUs, how they differentiate from other identifiers, and how to effectively manage them for optimal inventory control.

What is the Amazon FNSKU

The Amazon FNSKU, an abbreviation for "Fulfillment Network Stock Keeping Unit," is a unique identifier exclusive to Amazon's platform. Unlike the Universal Product Codes (UPC) used by various retailers, the FNSKU is specific to Amazon and instrumental in differentiating your products in the Amazon's warehouse.

FNSKUs are essentially barcodes that Amazon FBA sellers use on their products. They allow Amazon to connect each product with the seller's account, enabling accurate inventory tracking and streamlined fulfillment processes. By using an FNSKU, your inventory remains separate from other sellers', even when multiple sellers are selling under the same Amazon Standard Identification Number (ASIN).

The FNSKU vs. ASIN vs. UPC/EAN: Key Distinctions for FBA sellers

All three, FNSKU, ASIN, and UPC, are product identifiers, yet they serve distinct purposes and have different scopes of use.

The UPC, a universal identifier, can be used across various retail and online marketplaces, not only Amazon. A UPC identifies what the product is but does not specify who the seller is.

Conversely, the FNSKU is exclusive to Amazon, playing a pivotal role in accurate inventory tracking and order management. It identifies both the product and the seller, ensuring that the right seller is credited for each sale. This specificity makes the FNSKU invaluable for FBA sellers, who rely on Amazon for storage and shipping services.

ASIN, a unique identifier assigned by Amazon to each product, provides detailed product information, such as title, description, and images. The key difference between ASIN and FNSKU lies in their functionality. While ASINs primarily serve to identify products, FNSKUs facilitate inventory location and retrieval in Amazon's warehouses.

Are you interested in learning more ways to take control of your Amazon inventory? Click here to read our article on Amazon inventory reports.

The Importance of FNSKU Barcodes and Labels for Your Business

Employing FNSKUs as part of your Amazon business strategy can significantly enhance inventory management and reduce fulfillment errors. They improve product storage and retrieval efficiency for Amazon pickers, resulting in time and cost savings for FBA sellers, and ultimately lead to heightened customer satisfaction.

Another significant advantage of FNSKUs is their ability to prevent inventory commingling. Commingling is when similar products from different sellers are mixed in Amazon's fulfillment centers, which can lead to authenticity and quality control issues. Utilizing FNSKUs helps maintain the distinct identity of your inventory, significantly reducing the risk of commingling.

On another note, have you heard of stranded inventory on Amazon? This article explains Amazon stranded inventory in detail and will also tell you how to fix it

Create an FNSKU: A Practical Guide

Creating FNSKUs for your products is a straightforward process. Here are the steps:

Sign in to your Amazon Seller Central and navigate to the 'Manage Inventory' page.\

Select the product for which you need an FNSKU and click 'Edit'.\

In the 'Product Information' section, choose 'Fulfillment'.\

Click 'Change' next to the 'Amazon Fulfillment SKU' option, and follow the prompts.\

Remember, every unit of your product must be labeled with an FNSKU barcode. This can be done by you, your supplier, or you can pay Amazon to do the labeling at a nominal fee.


In the end, understanding and effectively managing FNSKUs can be an essential part of a successful Amazon FBA strategy. FNSKUs not only help improve inventory management, reduce fulfillment errors, and prevent inventory commingling, but they also ensure that you are credited for each sale of your product on Amazon.

Looking for an Amazon Fulfillment center near you? Read this article.

Learn More about the uses of FNSKU labels

FNSKU Label Requirements

When labeling your products with FNSKUs, you must adhere to Amazon's strict guidelines to ensure your products can be efficiently processed in their fulfillment centers. Labels should be clearly visible and readable, and not cover any other essential product information. The barcode should be easily scannable, and the label should not be placed on a curve or corner where it could be damaged or obscured. If your products don't meet these labeling standards, they may be rejected or subjected to additional processing fees.

FNSKUs and Returns

One of the often-overlooked advantages of using FNSKUs is the clarity they provide in handling returns. When a product is returned, Amazon can quickly identify the original seller using the FNSKU, ensuring that returns are correctly attributed and that any issues can be handled efficiently.

Changing FNSKUs

If you need to change an FNSKU for a product, be aware that this will require creating a new product listing in Amazon's system, as FNSKUs are linked to specific product listings. Also, any existing inventory in Amazon's fulfillment centers cannot be relabeled with the new FNSKU. Instead, it must be removed or sold under the old FNSKU.

FNSKUs in Different Marketplaces

It's also important to note that FNSKUs are marketplace-specific. If you sell your product in different Amazon marketplaces (for example, and, you'll have different FNSKUs for each marketplace. This is because each marketplace operates independently, with its own unique inventory tracking and order management systems.

FNSKUs and Product Bundles

If you're selling product bundles, each distinct bundle requires a unique FNSKU. This ensures accurate inventory tracking for bundles, which can significantly streamline the fulfillment process and reduce errors.

FNSKUs and Product Variations

For products with variations such as size or color, each variation requires its own FNSKU. This allows Amazon to accurately track inventory and sales for each specific variation, providing valuable data for inventory management and strategic decision-making.

In conclusion, mastering FNSKUs is not just about understanding what they are and how to generate them. It's about comprehending their impact on various facets of your Amazon business, including inventory management, order fulfillment, product returns, product variations, and global selling. With a firm grasp on FNSKUs, you can streamline your operations, enhance customer satisfaction, and ultimately, drive the growth of your Amazon FBA business.

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