FNSKUs, ASINS, UPCs, Barcodes Explained

Is your brain spinning with all these codes and acronyms?

When you sell on Amazon, there are some terms you will frequently hear and see used, and sometimes they can all get a bit confusing. What goes where? I need to purchase which? What do they all mean?

I am going to briefly explain some of the different terms related to your products and inventory, and how Amazon keeps track of them.

SKUs

SKU stands for stock keeping unit. You have most likely seen them when you have gone into a store or purchased something online. It might be 6 digits, or include letters.

Retailers use SKUs to track inventory levels, pricing, and other sales metrics at the store or company level. It is a number assigned by the merchant(as in you in this case).

Each listing of yours on Amazon will have it’s own merchant SKU which you create. There are different philosophies on how to come up with SKUs. For example, some sellers will encode their purchase price and date information into a sku for referencing later, but ultimately it is up to you to decide.

If you leave the merchant sku field blank when adding a product on Amazon, it will be filled automatically with something random.

FNSKU

Similar to SKU, FNSKU stands for fulfillment network stock keeping unit. This is an internal number which Amazon uses to track your Fulfillment by Amazon(FBA) inventory. In other words, if you fulfilling your products yourself, you will not have an FNSKU. Unlike a merchant SKU, this number is assigned by Amazon, not the seller.

When you ship a product into FBA, you will print out an FNSKU label which is a barcode you apply to your product packaging. This barcode allows Amazon to track and manage your product inventory in it’s warehouses.

Every time an Amazon employee handles your product, such as when Amazon moves inventory from one warehouse to another, they will scan the FNSKU label. Another example, is when an order is placed for your product. A warehouse employee will go to the appropriate bin which holds your product, scan the FNSKU and then the product will be packaged and shipped to the customer.

Meanwhile, your inventory and order information in seller central will be updated.

ASIN

While the FNSKU identifies a single seller’s specific inventory of a product, the Amazon Standard Identification Number, or ASIN identifies the product in the Amazon catalog. It is related to the product details on the listing page such as titles, photos, keywords etc. When looking at a product on Amazon, the ASIN is the 10 character code starting with a B that is in the URL bar of your web browser(Unless it is a book, which uses the ISBN rather than an ASIN).

The ASIN is also assigned by Amazon.

UPC

While ASINs and FNSKUs are used only by Amazon, the universal product code(UPC) is one of the most widely used global and unique identifiers for products. The UPC identifies a specific product, and it’s manufacturer. These numbers are each unique to a single product, and maintained in a database by a company named GS1.

You have seen these on the packaging of most products sold in retail stores. They are typically represented as a barcode with the number at the bottom.

UPCs are one type of unique product identifier used by Amazon to add products to the catalog. One alternative to purchasing UPCs, is to apply for Amazon’s Brand Registry, which allows you to add products without using a UPC.

Summary

You can think of each of these as a sort of descending hierarchy from the global level to the individual seller. UPCs being a global unique identifier, ASINs denote a product and possibly multiple sellers on Amazon, the FNSKU tracks a specific seller’s FBA inventory, and finally the merchant SKU is a seller level inventory code.

One thing to keep in mind, is that when sending inventory into FBA there should only be one barcode visible and able to be scanned on the unit’s packaging: The FNSKU label. Any other existing barcodes, such as the original UPC label should be covered.

Hopefully this has helped clear up any confusion regarding these different terms and how they apply to your Amazon business!