X00 barcode: the Amazon FNSKU explained
A barcode whose number starts with X00 is an Amazon FNSKU. Amazon assigns it to one seller's offer of one product, and fulfillment centers scan it to know whose unit they are holding.
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What an X00 barcode is
FNSKU stands for Fulfillment Network Stock Keeping Unit. Amazon's own FBA guide describes it this way: product labels are printed with the FNSKU, and for labeled inventory the FNSKU begins with X00 and is unique to both your seller account and the Amazon ASIN. Two sellers of the same product therefore have two different X00 codes.
The code is 10 characters of capital letters and digits, for example X001ABCDE9. On the label it is printed as a Code 128 barcode with the same 10 characters in plain text underneath.
| Code on the listing | Looks like | What it means |
|---|---|---|
| FNSKU | X001ABCDE9 | Amazon barcode. Each unit needs this label. |
| ASIN | B08N5WRWNW | The catalog ID. If the FNSKU column shows this, the listing is tracked by its manufacturer barcode. |
| UPC-A | 036000291452 | The manufacturer's retail barcode, 12 digits. |
Where to find your X00 code
The code is in Seller Central, not on the product. Amazon documents two places to get it:
- Manage FBA Inventory: select the products, choose Print Item Labels from the drop-down menu and click Go. Amazon generates a PDF sheet of labels.
- The shipment creation workflow: enter the number of units for each product and click Print item labels.
- The FNSKU column of your FBA inventory lists the same code if you only need to copy it.
What goes on the label
Amazon's label is plain: the barcode, the FNSKU under it, the product name and the condition. Its guide lists the rules for using it:
- Each unit needs its own FBA product label.
- Cover any original barcodes with the FBA product label, so receiving does not scan the wrong one.
- Match each label to the unit it belongs to. An X00 code on the wrong product assigns that unit to the wrong listing.
- Labels must be readable and scannable. Amazon recommends white label stock with removable adhesive.
- Print without scaling. A sheet printed at Fit to page drifts off the die-cuts by the bottom rows.
Label sizes Amazon supports
Seller Central offers eleven label templates. For US Letter paper the one that matters is 30 labels per page at 1 × 2⅝ in, which is the Avery 5160 and 8160 layout. The rest are A4 sheets of 21, 24, 27, 40 or 44 labels.
Seller Central has no template for a thermal roll, which is why sellers with a Zebra or Rollo printer either crop the 30-up PDF or regenerate the labels at 2 × 1 in, one per page.
| Stock | Label size | Per page | Printer |
|---|---|---|---|
| Avery 5160 / 8160 | 1 × 2⅝ in | 30 | Laser or inkjet |
| A4, 63.5 × 38.1 mm | 63.5 × 38.1 mm | 21 | Laser or inkjet |
| Thermal roll | 2 × 1 in | 1 | Zebra, Rollo and similar |
Printing X00 labels yourself
Seller Central prints one product per page, so three products with ten units each use three sheets and leave sixty labels blank. If you already know your X00 codes you can lay them out yourself: type or paste each code with its title, condition and quantity, choose Avery 5160 or a 2 × 1 in roll, and download the PDF.
Whichever tool you use, scan one printed label before you label the shipment and compare the result with the FNSKU in Seller Central.
Amazon FNSKU Label Generator
Single PNG or SVG free. Full sheets: 3 free on sign-up.