FNSKU (Fulfillment Network SKU)
Last updated: March 17, 2026
FNSKU defined: What is the Fulfillment Network SKU?
The FNSKU (Fulfillment Network Stock Keeping Unit) is a unique, Amazon-generated product identifier for the FBA program. It combines the product's ASIN with the seller's identity, allowing Amazon to assign every unit in the warehouse to a specific merchant.
Unlike universal barcodes such as the EAN, the FNSKU is relevant only within Amazon. It is applied as a barcode on the product packaging and scanned by Amazon warehouse staff to store, pick, and – in the case of returns – route products back to the correct seller.
Table of contents
FNSKU vs. EAN: When do I need which?
The choice between FNSKU and EAN depends on your selling situation. Here are the most important differences:
FNSKU labeling
- + The product is uniquely assigned to you as the seller
- + No mixing with other merchants' goods (commingling)
- + Returns come back to you
- - Extra effort required for labeling
EAN labeling (manufacturer barcode only)
- + No additional labeling effort
- - Products can be commingled with other sellers' inventory
- - Other sellers' quality issues can affect you
- - No longer permitted as of March 2026 (see below)
Important: The FNSKU is the safer choice, because it prevents mix-ups and gives you full control over your inventory.
Creating and printing FNSKU labels
The FNSKU is generated automatically by Amazon as soon as you register a product for FBA shipping. Here is how to do it:
- 1. Log in to Seller Central
- 2. Go to “Inventory” → “Manage Inventory”
- 3. Select the product and click “Print” → “Item Labels”
- 4. Choose the label size and quantity
- 5. Download the PDF and print the labels
Tip: Use self-adhesive labels measuring 52 x 25 mm. The labels must completely cover any existing EAN barcode so that only the FNSKU can be scanned.
When is the FNSKU mandatory?
In certain product categories, FNSKU labeling has been mandatory for a long time:
- Food: For traceability in the event of quality issues
- Cosmetics and personal care: For hygiene reasons
- Topical products: Skincare products and similar items
- Baby products: Due to strict safety requirements
For all other categories, using the manufacturer barcode (EAN) was previously optional – but that is changing in 2026.
Recent changes in 2026
Important change as of March 31, 2026:
Amazon has announced that, as of March 31, 2026, all products – including those from resellers – must be labeled with an FNSKU. This brings so-called “commingling” (the mixing of products from different sellers) to an end.
What this means for you:
- All future FBA shipments must be FNSKU-labeled
- Inventory already stored without an FNSKU can continue to be sold
- Plan the changeover of your labeling process early
- Amazon offers a paid labeling service
Frequently asked questions (FAQ)
Can Amazon handle FNSKU labeling for me?
Yes, Amazon offers the FBA Label Service. With it, Amazon labels your products for a fee (currently around €0.30 per unit). This can make sense if you don't want to set up your own labeling process.
What happens if I send in products without an FNSKU?
Products without correct labeling can be rejected by Amazon. In the worst case, they are returned at your expense or destroyed. As of March 2026, this will be handled even more strictly.
Does my FNSKU change if I relist the product?
The FNSKU is tied to the combination of ASIN, seller ID, and product condition. If you relist the same product under the same ASIN, the FNSKU stays the same. With a new ASIN or a different condition (e.g. “used” instead of “new”), you receive a new FNSKU.
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