Amazon FNSKU Labels: What FNSKU Is and How to Label Every FBA Unit You Ship

Every unit you ship to an Amazon FBA fulfillment center must carry a unique FNSKU label. Without it, Amazon's receiving scanner can't route your inventory to the right ASIN — and if your items get commingled with another seller's, customers can end up with the wrong product (a major liability if quality differs).

FNSKU is the X00-prefixed 10-character identifier Amazon issues per SKU. You find it in Seller Central under Manage Inventory; you print it as a Code 128 barcode on a removable sticker; you apply it over any manufacturer barcode on the unit.

Step by step

1
Get your FNSKU from Seller Central
Manage Inventory > pick the SKU > FNSKU column. It always starts with X00.
2
Generate the barcode
Paste the FNSKU into our generator above. Output is a Code 128 barcode at the standard FBA label size.
3
Print on 1×2 inch removable labels
Amazon's spec: 1×2 inch (25×51 mm) labels, thermal direct or laser-printed, removable adhesive. Use 30-up Avery sheets or a thermal label printer.
4
Apply to each unit
Stick the FNSKU flat on the product. If the unit already has a manufacturer UPC, cover it completely so scanners don't read the wrong code.
5
Box and ship
Print the inbound shipment label from Seller Central (separate from FNSKUs). Box up, hand to your carrier, and Amazon receives.

Gotchas

FNSKUs are per-SKU, not per-unit — all 1,000 units of the same SKU share the same FNSKU. Pre-print a roll.
If your manufacturer's UPC is still visible alongside the FNSKU sticker, FBA receivers may scan the wrong one and reject the shipment.
Generic Brand-Registry sellers in some categories can use stickerless inventory (Amazon prints/applies FNSKU at the fulfillment center). Most sellers should still label themselves for control.
Don't print FNSKU labels with low-contrast ink — Amazon's scanners reject ambiguous prints and you'll get a 'no barcode found' error during receiving.

FAQ

Do I have to label every unit, or just the case?

Every individual unit. The master case also gets a separate Amazon shipment label, but each retail unit inside needs its own FNSKU.

Can I use the manufacturer's UPC instead of an FNSKU?

Only if you're enrolled in Amazon's stickerless / commingled inventory program (Brand Registry, eligible categories). Otherwise no — FBA needs FNSKU to track your specific units.

How big should the FNSKU label be?

1×2 inch (25×51 mm). Smaller doesn't scan reliably; larger wastes label real estate.

Can I generate 1,000 FNSKU labels at once?

Yes — upgrade to the Pro plan and use the Bulk CSV download. You can also export an Avery-30-up PDF for sheet-printing.

FNSKU generator — standalone generator without Amazon steps.
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