Note: There is another option called an EAN. It is similar to a UPC, so throughout this article, I’ll only refer to UPC codes, which are more common. For the purpose of this tutorial, they can be used interchangeably.
The first thing to understand is that both a UPC and an FNSKU are really just a series of characters (numbers and letters) used as a unique identifier for a product. Both can be represented as a simple set of characters, or visually represented as a barcode.
So, let’s take a look at a real example: The Webkinz Sweetheart Pup with Trading Cards
The UPC code for this product is
As I mentioned, this series of numbers can also be represented visually as a barcode so it can be scanned with a barcode reader. This makes it easy for a product to be identified for retail use and related logistics. The barcode for this product is below, and you likely see something similar every day:
For our purposes, an FNSKU code isn’t really any different than a UPC code except that it’s unique to Amazon. This is what an FNSKU code might look like:
So, keep these basic descriptions in mind, but let’s take a step back for a second.
When you create a listing on Amazon for a product that doesn’t already exist in their catalog, they need a way to uniquely identify that product. Since UPC codes are universally accepted in retail, it’s required to have one when you list a product.
Now, it doesn't matter whether you’re listing an existing branded product, or a brand new private label product that you created. Either way, a UPC number is required to create a new listing. For this purpose all you need is the number, not the barcode.
Remember, that’s the difference between:
UPC: 045635434868 (UPC Number)
Note: If you want to sell an item that already exists on Amazon, you won't need to add the UPC code yourself, since the seller who created the original listing will have included it at that time.
Once you’ve create a listing on Amazon, they will assign their own unique identifier, called an FNSKU (Fulfillment Network Stock Keeping Unit). While the UPC code helps Amazon keep track of millions of different products to be used on their site, the FNSKU helps them keep track of inventory for different sellers in their fulfillment centers. So a single product will have a unique UPC code, but if 3 different sellers are offering that same product for sale on Amazon, they will each have their own unique FNSKU so Amazon can keep track of inventory between all these sellers.
To put it another way, let’s use the Webkinz Sweetheart Pup with Trading Cards example again. The UPC code for this product is 045635434868, and that won’t ever change. However, if we have three sellers for this product, Amazon will have to keep track of their inventory separately, so they will each be assigned a unique FNSKU code for that particular product.
This is why when you list an item for sale on Amazon, there will be a UPC (unique to the product) and an FNSKU (unique to the seller for that product).
So, now you might be wondering when you need each one and which should be placed on your product. This is actually where the decision of whether or not to use the Stickerless Commingled Inventory option comes in to play, so I’d recommend you read through my wiki article on the subject: Stickerless Commingled vs. Stickered Inventory.
This post is part of the Ultimate Wiki Project