Amazon FNSKU vs UPC and EAN: which barcode goes on your product?
Sellers using Fulfilment by Amazon (FBA) meet two barcodes and often mix them up. They do different jobs, and most FBA sellers need both.
The two numbers
| UPC or EAN (GTIN) | FNSKU | |
|---|---|---|
| What it identifies | The product, for every shop that sells it | Your units of the product, inside Amazon's warehouses |
| Who issues it | GS1 (licensed to the brand owner) | Amazon, when you set up the listing for FBA |
| Looks like | 12 or 13 digits | 10 characters, usually starting with X00 |
| Barcode type | UPC-A or EAN-13 | Code 128 |
| Needed for | Creating a listing (unless exempt) | Sending stock to FBA with Amazon barcodes |
Why Amazon wants a GTIN
To create a new product listing, Amazon asks for a product ID: a UPC, EAN, ISBN or JAN. It checks the number against the GS1 database and expects the brand on the listing to match the company that owns the number. Numbers bought cheaply from resellers often fail this check. If your product genuinely has no barcode, such as handmade or private-label goods sold only on Amazon, you can apply for a GTIN exemption. See how to get real product barcodes.
Why Amazon adds an FNSKU
Many sellers can sell the same product, and they all share its GTIN. The FNSKU (Fulfilment Network Stock Keeping Unit) tells Amazon which seller's stock a unit belongs to, so your units are counted as yours and customer returns come back to you. Amazon creates it when you list the product for FBA and shows it in Seller Central next to the ASIN.
Amazon barcode or manufacturer barcode?
In Seller Central you choose which barcode Amazon uses to track your FBA stock:
- Amazon barcode (FNSKU): you, or Amazon for a fee, put an FNSKU label on every unit. Your units stay separate from other sellers'. This is the safer choice for most sellers.
- Manufacturer barcode: Amazon scans the UPC or EAN already on the pack, so no labels are needed. Units that qualify may be mixed with identical units from other sellers, which saves work but means a customer may receive another seller's unit.
Printing FNSKU labels that scan
- Print labels from Seller Central's shipment workflow; Amazon lays out the barcode, a short product title and the condition.
- Print at 100% scale on white labels. A thermal label printer at 203 or 300 dpi is ideal.
- Cover any other barcode on the unit, so the warehouse scanner can only find the FNSKU.
- Keep the label flat, away from edges and corners, and outside any shrink-wrap that would wrinkle it.
- Scan a few labels with a phone barcode app before you ship.
The FNSKU is an ordinary Code 128 barcode, so if you need to reprint one outside Seller Central you can make it with any Code 128 generator. Keep the module at 0.25 mm or more and leave the quiet zones clear.
Setting it up
- Get a GTIN for the listing. A UPC or EAN from GS1, or a GTIN exemption from Amazon for products that have none.
- Choose the barcode type in Seller Central. Amazon barcode (FNSKU) keeps your units separate; manufacturer barcode lets Amazon use the UPC or EAN on the pack.
- Print the FNSKU labels. From the shipment workflow, on a thermal or laser printer, at 100% scale.
- Cover the old barcode. Each unit should show only one scannable barcode: the FNSKU label.
- Scan a few labels before shipping. Any phone barcode app should read the FNSKU starting with X00.