Amazon FBA Label Requirements: The Definitive 2026 Guide
Getting your labels wrong on an Amazon FBA shipment is expensive. Amazon charges a $0.20 per-unit relabeling fee (as of 2026) when items arrive with unreadable or incorrect labels. Box labels that fail scanning at the fulfillment center (FC) can trigger a "problem shipment" hold, delaying your inventory by days or weeks and costing you in-stock sales rank. For LTL shipments, a rejected pallet can result in the entire truck being turned away.
This guide covers every label type you need for an FBA shipment, the exact specifications Amazon requires, how scanning works at Amazon FCs, and what actually causes rejections.
Key Takeaway
Amazon's labeling requirements haven't fundamentally changed since 2020, but enforcement has tightened considerably. FCs now reject shipments they would have accepted three years ago. Getting this right once saves significant ongoing cost.
FNSKU Labels: Unit-Level Requirements
The FNSKU (Fulfillment Network Stock Keeping Unit) label goes on every individual sellable unit in your FBA shipment. It is how Amazon's warehouse management system (WMS) tracks your specific inventory, separate from other sellers' inventory of the same product.
Physical Specifications
- Minimum size: 1 inch × 1 inch (25.4 mm × 25.4 mm)
- Recommended size: 1 inch × 2 inches or 2 inches × 1 inch — gives the barcode more room to breathe and scans more reliably
- Background: White or near-white only. Yellow, silver, and textured backgrounds cause scan failures
- Barcode type: Code 128 (1D linear barcode)
- Human-readable text: Must appear below the barcode — this is the FNSKU string (e.g.,
X001ABC123) plus the product title (truncated) - Quiet zones: At least 1/8 inch of blank space on both sides of the barcode
- Print quality: Minimum 300 DPI for thermal printing; inkjet is acceptable if the barcode edges are sharp and the background is white
FNSKU Format
An FNSKU always starts with X0 and is 10 characters long: X001234567. It is generated by Amazon and is unique to your seller account + ASIN combination. Two different sellers selling the same product will have different FNSKUs. This is by design — it enables commingled inventory tracking.
What Must Appear on the FNSKU Label
Amazon requires:
- The scannable Code 128 barcode encoding the FNSKU
- The human-readable FNSKU string directly below the barcode
- The product name or description (can be truncated)
- "Made in [country]" if required by the product category (electronics, food, etc.)
The following are not required but are good practice: condition (New/Used), expiration date (required for some categories like food and supplements), lot number.
Covering Existing Barcodes
If the product already has a manufacturer barcode (UPC/EAN), you must cover it completely with the FNSKU label. Amazon's FC scanners work by scanning the first barcode they see. If an old UPC is visible, the scanner may read it instead of the FNSKU, routing your item into the commingled pool.
Use an opaque label stock. A partial cover that lets the UPC bleed through is a common cause of mislabeled inventory chargebacks.
Where to Place the FNSKU Label
- Poly-bagged items: On the outside of the bag, not underneath
- Boxed items: On the outside surface most visible when shelved (usually the side panel, not the bottom)
- Multi-packs: On the outer packaging, covering all individual-unit barcodes inside
- Expiration-date products: FNSKU label should not cover the expiration date
Box Labels and Pallet Labels
Each carton in your FBA shipment needs a box label (also called a carton label or shipping label) that Amazon uses to check in your shipment at the FC. This is separate from the carrier shipping label.
Format and Specifications
Amazon generates box labels in your Seller Central account when you create the shipment. They are delivered as PDFs. The barcode format is GS1-128 (a subset of Code 128 with specific application identifiers).
The box label contains:
- A GS1-128 barcode encoding the shipment ID and box sequence number
- The shipment ID (e.g.,
FBA17ABC1234) - The box number (e.g.,
Box 1 of 5) - The FC destination address
- Your merchant/seller name
Required label size: 4 inches × 6 inches
Placement: Applied to the side of the box — not the top (which gets stacked on) and not the bottom. If a box has more than one non-sealed opening (e.g., a lid), apply the label to the flap side.
One label per box: Do not apply duplicate box labels. If a box gets re-packed, print a fresh label and remove or obliterate the old one.
When to Use Two Box Labels
If your carton is longer than 18 inches on any side, Amazon recommends applying a second box label on an adjacent face. Large boxes get handled differently in FCs and may be positioned in ways that obscure a single label.
Pallet Labels: LTL Shipment Requirements
If your shipment ships via LTL (Less than Truckload) freight, each pallet needs four labels — one on each face, positioned 3–4 feet from the ground (or in the upper third of the pallet if the pallet is shorter than 3 feet).
Pallet Label Contents
Amazon's pallet label includes:
- A barcode (Code 128 or GS1-128) encoding the pallet ID
- The shipment ID
- Amazon's FC destination address
- The number of cases on the pallet
Pallet labels must be generated from Seller Central in the LTL shipping workflow. You cannot use generic pallet labels.
Physical Requirements
- Size: 4"×6" thermal label or standard letter-size paper (must be folded into a document sleeve)
- Placement: On all four sides, in the upper third of the pallet, not on the shrink wrap (which can tear)
- Legibility: Labels must be readable without moving the pallet
Commingled vs. Non-Commingled Inventory
This is one of the most consequential decisions for FBA sellers. It directly affects what barcode Amazon uses to track your units.
Commingled Inventory (Amazon Barcodes)
When you opt into Amazon's "commingled" program, Amazon removes your FNSKU requirement and uses the manufacturer's UPC/EAN to track items. Your unit of Product A may be stored alongside another seller's units of the same Product A and fulfilled interchangeably.
The risk: If another seller sends in counterfeit or lower-quality versions of the same product, Amazon may fulfill those units to your buyers. You bear the customer service consequences even though you didn't ship the bad units.
The benefit: You don't have to label every unit.
Non-Commingled Inventory (Merchant-Owned Barcodes)
With the FNSKU labeling requirement, Amazon segregates your inventory from all other sellers' inventory of the same product. Your unit fulfills your order.
Most serious FBA sellers use FNSKU labeling. The commingled risk is not worth the labeling cost savings, particularly for premium or branded products.
How Amazon Scans Labels at the FC
Understanding the scanning workflow helps you understand why certain errors cause rejections.
When your shipment arrives at an Amazon FC:
- Inbound dock scan: The driver's BOL (Bill of Lading) and pallet labels are scanned. The system confirms the shipment is expected.
- Carton check-in: Each box label is scanned. The system records how many boxes arrived vs. expected.
- Unit receive: Items are moved to a "receive" station where workers scan each FNSKU label. The system counts units and routes them to storage bins.
- Stow: Units are stowed into random-access storage bins. The bin location is associated with the FNSKU in the WMS.
Amazon FCs use a mix of laser barcode scanners and camera-based 2D imagers. Code 128 barcodes are read by both. QR codes and Data Matrix are read by imagers only. Amazon does not accept QR codes on FNSKU labels — always use Code 128.
Common Rejection Reasons and How to Avoid Them
Key Takeaway
Always test-scan your FNSKU labels with a phone barcode app before the full shipment leaves your facility. A 30-second check on 3 random units can save a $200 Amazon relabeling fee on a 1,000-unit shipment.
1. Unreadable Barcode
Cause: Low print DPI, smeared ink, wrinkled label, or insufficient quiet zone.
Fix: Print at 300 DPI minimum on a thermal printer. Never print FNSKU labels on an inkjet with low quality settings. Always test-scan with a phone barcode reader before shipping.
2. Wrong Barcode Type
Cause: Using a UPC or ASIN instead of the FNSKU as the scannable data.
Fix: Generate labels from Seller Central's "Print Item Labels" workflow, which automatically uses the FNSKU. Don't manually create barcode images from the ASIN string.
3. Label Applied Over Expiration Date
Cause: The FNSKU label was placed on the panel containing the expiration date.
Fix: Rotate the label placement. If space is tight, use a smaller 1"×1" FNSKU label and position it away from the expiration date.
4. Mismatched Box Count
Cause: Shipped 5 boxes, declared 4 in the shipment — or vice versa.
Fix: Always update the box count in Seller Central before shipping. Use the "Work on Shipment" workflow and confirm quantities.
5. Wrong FC Destination
Cause: Labels from a previous shipment were accidentally used, or the shipment was split and the wrong cartons got the wrong labels.
Fix: Print labels fresh for every shipment. Color-code cartons by destination FC if you have a split shipment.
Generating Compliant Labels: Tools and Workflow
Amazon's Seller Central generates both FNSKU labels and box labels as PDFs in the correct format. For low-volume sellers, this is sufficient.
For sellers operating at scale — especially those using a 3PL for FBA prep — the label workflow often starts with ZPL files output by a WMS or ERP system. These ZPL files contain the FNSKU barcodes and need to be converted to PDFs that match Amazon's size requirements before printing.
Zentralabel converts ZPL label files to high-resolution PDFs in bulk, so your prep center can receive a batch of 500 ZPL files and produce print-ready PDFs in seconds without needing a Zebra printer on every workstation. The output is 300 DPI and Code 128-accurate, meeting Amazon's specifications.
Category-Specific Label Requirements
Some product categories have additional labeling requirements beyond the standard FNSKU:
- Food and consumables: Expiration date must be visible on the unit AND on the label if the product ships as "Add-on" (sold as part of a bundle)
- Poly-bagged items: Suffocation warning text must appear on the poly bag itself (not the label), in a minimum 10-point font
- Transparent packaging: If the product is visible through packaging, the FNSKU label must still be on the outside of any transparent layer
- Multi-pack bundles: A sticker reading "Sold as Set" must appear on the bundle packaging in addition to the FNSKU
- Hazmat/Dangerous Goods: Additional GHS/SDS hazmat labels required; Amazon has separate FC routing for these
Always check the Amazon Seller Central Help page for your specific category, as requirements update periodically.
Ready to streamline your FBA label workflow? Try Zentralabel to convert and preview your ZPL label files before they reach your prep center.