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Free FNSKU Label Generator: Amazon FBA Barcodes for Prep Centers & Self-Shippers
FNSKU (Fulfillment Network Stock Keeping Unit) is Amazon's internal per-unit identifier for FBA inventory. Every unit you send to an Amazon fulfillment center must carry an FNSKU label so Amazon can route it correctly, even when it gets commingled with units of the same ASIN from other sellers (unless you're enrolled in stickered inventory, which makes the FNSKU mandatory).
Validator
Paste an existing FNSKU into the field above. We compute the check digit if you provide just the payload, verify it if you provide the full code, and refuse to render if the check digit is wrong — so anything that renders here is guaranteed to scan.
Amazon issues FNSKUs from Seller Central — they always start with 'X00' and are 10 characters total. Use this page to render an FNSKU you've been assigned into a scannable barcode at standard 1×2-inch prep-center label size, or click Randomize to test the format.
Structure
10 alphanumeric characters: 'X00' prefix followed by 7 random uppercase letters and digits. Rendered as a Code 128 barcode underneath, with the FNSKU text printed below the bars.
When to use FNSKU
- Every unit shipped to Amazon FBA (not just the master case — every individual unit)
- Prep-center workflows when outsourcing FBA labeling
- Reprinting damaged or missing FNSKU labels at the seller end
- Testing FBA label software / printer configurations before going to production volume
Where it's required
- All FBA inventory by default. Enrolling in Brand Registry can allow stickerless commingled inventory in some categories, but most sellers still use stickered FNSKUs.
- Required on the unit, separate from any UPC printed by the manufacturer on retail packaging.
FAQ
What is an FNSKU label?
FNSKU stands for Fulfillment Network Stock Keeping Unit. It's a unique Code 128 barcode (starting with 'X00') that Amazon assigns to each of your FBA SKUs. Every unit shipped to an Amazon fulfillment center must have an FNSKU label so Amazon can track inventory back to your seller account, distinguishing your units from other sellers' identical products.
Are SKU and FNSKU the same?
No. A SKU is your internal product code — you set the format and naming convention; it's private to your business. An FNSKU is Amazon's barcode for your product inside their fulfillment centers — Amazon generates it, format is fixed (X00 prefix + 7 alphanumeric chars). Every SKU has exactly one FNSKU.
Where can I find FNSKU labels?
In Seller Central: Inventory → Manage Inventory → find your SKU → click the action dropdown → 'Print item labels'. Choose label size and quantity, download as PDF, print on 1×2 inch removable labels. The PDF contains your FNSKU as a Code 128 barcode plus the human-readable text below.
Are ASIN and FNSKU the same?
No. ASIN identifies the product listing in Amazon's catalog (visible to shoppers on the product page). FNSKU identifies which physical unit belongs to which seller in Amazon's fulfillment centers (used only behind the scenes). One ASIN can have multiple FNSKUs from different sellers offering the same product.
How do I get an FNSKU label?
Sign in to Seller Central → Inventory → Manage Inventory → find your FBA SKU → open the action menu → select 'Print item labels' → choose quantity and label format → download the PDF. As of January 2026, Amazon no longer applies FNSKU labels for you — you must apply them before shipping to FBA.
What size should the FNSKU label be?
Amazon spec: 1×2 inch (25×51 mm) removable label, printed in black ink on a white non-reflective surface. Apply flat over any existing manufacturer barcode (UPC, EAN) to prevent the FC scanner from reading the wrong code.