Barcode Requirements for Amazon FBA Sellers (Guide)

Amazon FBA rejects a surprising number of listings over barcode issues, not because sellers are careless, but because the requirements aren’t as obvious as they seem. Getting this wrong delays your inventory getting into Amazon’s warehouse at all.

What Amazon Actually Requires

Amazon requires each product to have a scannable barcode tied to a unique identifier, typically a GS1-registered UPC or EAN, or Amazon’s own FNSKU (Fulfillment Network Stock Keeping Unit) if you’re using FBA.

Want to learn more? Explore our related QR code and barcode guides for more helpful tips, how-to guides, and useful information.

What an Amazon Barcode Actually Looks Like

An amazon barcode example makes this easier to picture. A standard UPC looks like a regular retail barcode, a row of black bars with a 12-digit number underneath it, like 012345678905. An FNSKU looks similar but encodes an alphanumeric code instead, something like X001A2BCDE, printed above or below the bars along with the product title in small text. The FNSKU is what Amazon’s warehouse scanners are actually looking for on FBA inventory, not the UPC.

UPC/EAN vs FNSKU: The Key Distinction

  • UPC/EAN identifies your product universally across retail, this is what you register with GS1 and use when first creating a listing.
  • FNSKU is Amazon-specific and identifies your inventory as belonging to your seller account within Amazon’s fulfillment system. For FBA specifically, Amazon generally requires the FNSKU barcode on the product itself (not just the UPC), so their warehouse system can track it correctly.

Common Rejection Reasons

  • Using a cheap, unregistered UPC bought outside GS1. Amazon has cracked down on this and may flag or delist products using unverified codes.
  • Only printing UPC without FNSKU on FBA inventory. Many sellers assume UPC alone is enough, but Amazon typically needs the FNSKU label for its own warehouse scanning process.
  • Low-quality barcode printing. Smudged or low-resolution labels get physically rejected at Amazon’s receiving centers, causing shipment delays.
  • Wrong label size or placement. Amazon has specific guidelines for label size and where it must be placed on packaging, codes placed on curved or seamed surfaces often scan poorly.

Practical Tips

  • Get your UPC/EAN through GS1 directly, not third-party resellers, to avoid future delisting risk.
  • Generate your FNSKU labels through Amazon Seller Central (they provide these once your listing is created), don’t try to substitute your own barcode for this specific label.
  • Print at high resolution and test-scan before shipping a full pallet to Amazon’s warehouse.

Real Use Case

A new FBA seller ships their first batch of inventory using only their UPC barcode, unaware Amazon required a separate FNSKU label for warehouse processing. The shipment gets flagged and delayed at the fulfillment center, costing them a week before it’s corrected, a mistake avoided entirely by generating and applying both barcodes from the start.

Wrapping Up

Amazon FBA needs both a registered UPC/EAN for the listing and, in most cases, Amazon’s own FNSKU barcode for warehouse tracking, treating them as interchangeable is the most common cause of shipment delays. Our Barcode Generator handles UPC/EAN creation cleanly. FNSKU labels specifically need to come from your Amazon Seller Central account.

FAQ’s

In most cases, yes — UPC/EAN identifies the product for the listing, while FNSKU is Amazon’s own tracking code needed for warehouse fulfillment.

It’s risky — Amazon increasingly requires GS1-registered UPCs and has delisted products using unverified third-party codes.

Directly from Amazon Seller Central once your product listing is created — it’s not something you generate independently like a UPC.

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