UPC vs FNSKU: Which Amazon Barcode Do You Need?

Last checked against Amazon Seller Central and Amazon's own seller pages: November 1, 2026. Amazon changes these rules; confirm in your account before you ship. We are not affiliated with Amazon or GS1.

The short answer

Amazon barcode requirements

UPC vs FNSKU is easier once you see Amazon's barcode requirements side by side. In short, as of November 1, 2026:

• To list a new product: a GTIN, usually a 12-digit UPC, licensed from GS1 to your brand. Products with no barcode can get a GTIN exemption instead. More on when you need a UPC.
• To send units to FBA: an Amazon FNSKU label on every unit, unless you are the brand owner with the Brand Representative role and Amazon tracks that product by its manufacturer barcode. More on FNSKU labels.
• Label size and print: FNSKU labels 1 to 2 inches tall and 2 to 3 inches wide, black on non-reflective white, covering any other barcode on the unit.
• UPC barcodes on packaging: a scannable UPC-A between 80% and 200% of the standard size, with its blank side margins (quiet zones) kept clear. See UPC barcode size and the label sizes that fit.

UPC vs FNSKU at a glance

When you need a UPC for Amazon

To create a new product page, Amazon asks for a product ID. Amazon has said since at least 2020 that for most categories you must provide a unique GTIN, that GTINs are invalid if they are not GS1-issued or not recognised by the brand owner, and that you should get them directly from GS1 (Amazon Seller Forums announcement, posted 2020). GS1 US's current Amazon page adds that Amazon checks product UPCs against the GS1 database, so the brand on your listing should match the company the number is licensed to (GS1 US: barcodes for Amazon, checked November 1, 2026).

• Your own brand: license UPCs from GS1 (see how to get a GS1 UPC) and give each variant its own number.
• Reselling someone else's product: you add your offer to the existing listing; the brand's UPC is already there.
• No barcode at all (private label, handmade, some bundles): apply for a GTIN exemption in Seller Central. It covers a brand and category, not every product you'll ever sell, and a GS1 UPC is still the better choice if you plan to sell beyond Amazon.

Not sure how UPC relates to EAN and SKU? See UPC vs EAN vs SKU.

When you need an FNSKU label

The FNSKU (Fulfillment Network Stock Keeping Unit) is how Amazon's warehouses know a unit is yours and not another seller's identical product. Amazon creates it when you set a product up for Fulfillment by Amazon. You don't buy it, and it can't be worked out from the UPC or the ASIN.

You need an FNSKU label on every unit whenever the product isn't tracked by its manufacturer barcode: for most resellers since March 31, 2026, and for anyone whose product has no scannable manufacturer barcode. Amazon's FBA prep guide (dated July 7, 2026) also lists cases that always need Amazon barcodes, such as used items and certain consumable or restricted products (Amazon FBA prep guide).

What Amazon asks for, from the same guide (checked November 1, 2026):

• Size: labels 1 to 2 inches tall and 2 to 3 inches wide. A 2⅝″ × 1″ label, the size of 30-up sheets such as Avery 5160, sits inside that range.
• Print: black ink on non-reflective labels with adhesive backing; Amazon suggests a 300 dpi laser printer for best results.
• Placement: cover any original barcodes (UPC, EAN, ISBN) so they can't be scanned by mistake.
• Where to get them: print them from Seller Central for each product or shipment; Amazon fills in the FNSKU, product name and condition.

Whatever you print on, use the print at actual size settings so the labels line up.

Can I use the manufacturer barcode instead?

Until 2026, many FBA sellers used “stickerless, commingled” inventory: units were tracked by the manufacturer UPC, and Amazon could ship any seller's identical unit to a customer. Amazon has ended that. Its announcement, titled “Commingling practices will end effective March 31, 2026”, sets these rules for inventory shipped on or after that date:

Eligibility is set per product in Seller Central, and some product types still need Amazon barcodes regardless. Amazon's help pages explain how to switch to manufacturer barcodes, Brand Registry and the FBA barcode FAQ (you need to be signed in to Seller Central to read them).

Printing each label

UPC labels: for your packaging, retail stores, other marketplaces or brand-owner FBA units, use our free UPC label generator to print UPC labels on Avery sheets or thermal rolls, sized to GS1 rules.

FNSKU labels: print them from Seller Central today. Our generator does not make FNSKU labels yet: it prints UPC-A barcodes only. Amazon FNSKU labels, kept separate from your UPC records, are planned for Pro (planned at $10/month, not available yet). Join the waitlist if you'd like to hear when they're ready.