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Amazon FBA Barcode Generator — UPC, FNSKU & Label Guide
Last updated: April 2026
Amazon FBA (Fulfilled by Amazon) has specific barcode requirements that differ from standard retail barcoding. Every product sent to an Amazon fulfilment centre must be correctly labelled — either with the manufacturer's UPC or EAN barcode already on the packaging, or with an Amazon FNSKU label applied over or instead of it. Incorrect or missing barcodes are one of the most common causes of FBA receiving errors, stranded inventory, and commingling problems. This guide explains exactly what is required, when each barcode type applies, and how to generate print-ready label files using BatchPrintGTIN.
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Generate FNSKU Label (Code 128) ·
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The Two Amazon FBA Barcode Systems
Amazon uses two fundamentally different barcode systems for FBA inventory, and understanding the distinction is essential before sending your first shipment.
UPC / EAN — The Manufacturer Barcode
The UPC-A or EAN-13 barcode on your product packaging is what most people think of when they imagine a barcode. For Amazon, this is the barcode that identifies what the product is — it links to your ASIN in Amazon's catalogue. If you opt into Amazon's "Stickerless, Commingled Inventory" programme, Amazon scans this barcode at receiving, and your units are physically mixed in the same warehouse bin with identical units from all other sellers of the same ASIN. When a customer buys, Amazon ships whichever unit is closest — it could be yours or another seller's.
Commingled inventory is efficient for high-volume commodity items where all units are genuinely identical. It is a serious problem for private-label products, handmade goods, or any item where you need to know exactly which units customers receive. If a commingled unit is counterfeit, defective, or mislabelled, your seller account can receive negative feedback for someone else's product.
FNSKU — The Amazon Inventory Barcode
An FNSKU (Fulfilment Network Stock Keeping Unit) is a unique Code 128 barcode assigned by Amazon to a specific combination of your seller account and ASIN. When you label products with FNSKU barcodes, your inventory is tracked separately from all other sellers in Amazon's fulfilment network. Each FNSKU label must completely cover any existing manufacturer barcode on the product.
FNSKU numbers look like X001AB12CD — they always begin with X0 and contain letters and digits. Amazon generates the FNSKU code; you retrieve it from Manage Inventory in Seller Central, then use BatchPrintGTIN to format it as a Code 128 barcode image on a label sized and formatted to Amazon's specifications.
When Amazon Requires FNSKU Labels
Amazon requires FNSKU labelling (or charges a per-unit fee for Amazon to apply labels at the fulfilment centre) in the following situations:
- You are selling private-label products that are not listed by any other seller — commingled inventory would serve no purpose
- You opt out of commingled inventory in your FBA settings
- Your product category is on Amazon's restricted list for stickerless inventory (including some grocery, health, and beauty categories)
- Your product is enrolled in Amazon's Transparency anti-counterfeiting programme
- Your ASIN has previously been reported for counterfeit issues and Amazon has required FNSKU labelling as a condition
If you are just starting out with private-label FBA, default to FNSKU labels for every shipment. The operational cost is minimal (a few seconds per unit with the right label sheets), and the protection against commingling issues and account health problems is significant.
Amazon FBA Label Specifications
Amazon's published label requirements for unit barcodes in FBA shipments:
| Specification | Requirement |
|---|---|
| Label size | 1" × 2⅝" (25.4mm × 66.7mm) — standard Avery 5160 layout, 30 labels per sheet |
| Print method | Laser or inkjet at minimum 300 DPI; thermal transfer acceptable at 300+ DPI |
| Barcode format | Code 128 for FNSKU labels; UPC-A or EAN-13 for manufacturer barcodes |
| Human-readable text | FNSKU code and product title should be legible below or beside the barcode |
| Coverage | FNSKU labels must fully cover any existing manufacturer barcode — no overlap allowed |
| Placement | Flat, accessible surface; not on a seam, curve, or area subject to moisture |
| Colour | Black bars on white background; no coloured backgrounds for retail barcodes |
UPC Requirements for Creating Amazon Listings
Before you can apply FNSKU labels, you need to create an ASIN in Amazon's catalogue — and creating most new ASINs requires a valid GTIN. Amazon accepts GTIN-12 (UPC-A) or GTIN-13 (EAN-13) for new product listings. Amazon validates GTINs against GS1's global database, which means your barcode number must be registered to your brand through GS1 US or GS1 Canada. Codes purchased from third-party barcode resellers are not GS1-registered to your brand and will fail Amazon's GTIN validation.
The workflow is: register with GS1 → obtain your Company Prefix → assign GTINs to each product variant → generate the barcode images for your packaging using BatchPrintGTIN → create your Amazon listing using the GTIN → retrieve the FNSKU code Amazon assigns → generate FNSKU labels for your physical units.
Amazon Brand Registry and GTIN Exemption
If you manufacture your own products and are enrolled in Amazon Brand Registry, you may be eligible for a GTIN exemption in some product categories. A GTIN exemption allows you to create a listing without a manufacturer barcode. However, you still need an FNSKU label on each unit for FBA — the exemption only waives the requirement to have a UPC on the product itself. Apply for GTIN exemption through Brand Registry in Seller Central. Approval is not guaranteed and is assessed per product category.
Transparency Codes — Anti-Counterfeiting Labels
Amazon's Transparency programme assigns a unique 2D serialised code to every individual unit of a product. When you enrol a product in Transparency, each unit must have a Transparency code label (a small Data Matrix or QR-style code beginning with "AZ:") in addition to the FNSKU or UPC barcode. Transparency codes are generated and provided by Amazon after enrolment — you do not generate them yourself. However, you do need to apply them to every unit before shipping to a fulfilment centre. Batching the Transparency application process alongside your FNSKU labelling is standard practice for enrolled sellers.
Step-by-Step: Generating FBA-Ready Barcode Files
Get your FNSKU code from Seller Central. Go to Manage Inventory, find your ASIN, click Print Item Labels. Note the FNSKU code (e.g. X001AB12CD).
Open the BatchPrintGTIN generator and select FNSKU (Code 128). Enter your FNSKU code in the data field. Add your product title as the label text if desired.
Set bar height and width to fit Avery 5160. A bar height of 50–60px and width of 1.8–2.0 works well for a 1" × 2⅝" label at 300 DPI.
Click the PDF / Page Designer button. Select Avery 5160 as the paper layout. The designer fills 30 labels per sheet automatically. Paste your FNSKU barcode into each cell or use the batch CSV feature to populate all cells at once.
Export as PDF and print on Avery 5160 label stock. Use a laser printer at full quality — inkjet can smear if labels are handled. Always scan at least two labels per sheet before applying to product.
Frequently Asked Questions
Can I use the same UPC barcode for all variants of my product?
No. Each variant — different size, colour, scent, or configuration — must have its own unique GTIN and its own ASIN on Amazon. Using the same UPC for different variants causes catalogue errors and receiving failures at Amazon fulfilment centres. Each ASIN also receives a distinct FNSKU.
What is the difference between an ASIN and an FNSKU?
An ASIN (Amazon Standard Identification Number) identifies the product in Amazon's catalogue — it is the product itself regardless of which seller is selling it. An FNSKU identifies the inventory belonging to a specific seller for a specific ASIN — it is used within Amazon's warehouses to track which seller's stock is which. One ASIN can have one FNSKU per seller account.
Do I need a UPC barcode on my product packaging if I use FNSKU labels?
If you are using FNSKU labels that fully cover the packaging barcode, the underlying packaging barcode does not need to be scannable. However, if you sell the same product through retail channels (brick-and-mortar stores, your own website, other marketplaces) alongside Amazon FBA, you still need a proper GS1-registered UPC on the packaging for those channels. For Amazon FBA only, an FNSKU label is sufficient.
Can I generate FNSKU barcodes using BatchPrintGTIN?
Yes. Select Code 128 (or the FNSKU preset) as the barcode type and enter your FNSKU code exactly as Amazon provides it. BatchPrintGTIN generates a properly formatted Code 128 barcode that meets Amazon's FBA label specifications. Use the PDF Page Designer to format labels for Avery 5160 label sheets.
What happens if my product arrives at Amazon with a missing or unscannable barcode?
Amazon will either place the units in problem-receive status (requiring you to pay for relabelling), return the entire shipment at your expense, or charge a per-unit labelling fee if you have not opted out of Amazon labelling services. Always scan every label before shipping. Use 300 DPI minimum and print on a laser printer to avoid barcode scanning failures.