Amazon FBA Labeling Rules: FNSKU, Box Labels & Covers
Every rejected-carton horror story has a labeling failure somewhere in its ancestry. This is the complete labeling spec — the three label layers on every FBA consignment, where each one goes, and the details that decide whether a scanner reads your box in half a second or a receiving associate sets it aside.
Published 2026-04-09 · Last reviewed: September 2026
The direct answer
Every FBA consignment carries three labeling layers: an FNSKU on each sellable unit (or an approved manufacturer barcode), a shipment carton ID on every box, and — on palletized freight — pallet labels matching the shipment plan. Each label must be scannable, flat, unobstructed, and must fully cover any barcode it replaces. Print thermally at 300 dpi, place on flat faces away from seams, and verify with a scan gate before loading. Seller Central defines the current requirements — this article is the working translation.
Layer 1: The FNSKU on every unit
The FNSKU (Fulfillment Network SKU) is the barcode that identifies your specific product in Amazon's system — visually distinct with its characteristic prefix, printed in the label format Seller Central generates. When your goods are stickered, the FNSKU is what receiving scans at the unit level; it is also what tells Amazon these particular units are yours, decoupling your inventory from any other seller of a similar product.
The placement rules are stricter than they sound. The label sits on a flat, uncurved surface of the product or its packaging. It may not fold over an edge, wrap a curved surface, or sit on a shrink-wrap seam where a scannable line gets broken. And any pre-existing barcode beneath it must be fully covered — not pasted over at an angle leaving the original code readable at the edges.
The classic China sourcing scenario: the factory applies its own product barcode on every unit for its own inventory control. Harmless by itself — but every one of those barcodes must be opaque-covered or removed before your FNSKU goes on. This is a written spec item for your purchase order, not a phone call made after production.
Layer 2: The carton ID on every box
Where the FNSKU identifies the product, the carton ID (the barcode on the "Shipment ID" label your shipment plan generates) identifies the box. Each carton in the shipment carries its own label — the same shipment ID on every box is normal, but each label must match the current shipment plan, be the current version Amazon issued, and be scannable.
Three failure patterns dominate:
- Labels across seams. A carton ID placed over the tape line tears during opening — many receiving issues trace to nothing more exotic than this.
- Stale shipment plans. The plan was re-created after a change (a split shipment, a revised FC assignment), and half the boxes carry labels from the dead plan. Only ever print from the active shipment.
- Label reuse on cartons. Reused boxes must have all previous labels fully removed or covered — a box with three eras of shipment labels is a box a human has to adjudicate, and humans are slower than scanners.
Layer 3: Pallet labels and the outer face
Palletized deliveries add a fourth surface to label: the pallet itself, per the shipment plan's pallet labels, plus the practical requirement that carton IDs on the outer faces of the load face outward. Stretch wrap goes over labeled cartons — thin, clear wrap applied without folding keeps labels readable through it; wrap that wrinkles over the label face can defeat scanners. Where the load risks wrap-clouded labels, labeling a clear pouch or flat face on the outside of the wrap is the pragmatic fix.
The print-and-verify standard
| Spec Item | Standard | Why It Matters at the Gate |
|---|---|---|
| Print method | Direct thermal, 300 dpi, quality stock. | Smudge, fade and low-contrast kills more scans than missing labels do. |
| Placement | Flat face, no seams, no edges, no tape overlap, outward-facing on pallets. | Receiving will not hunt for your label; it must present itself. |
| Cover rule | Old barcodes fully covered by opaque label or removed. | Dual-readable codes create wrong-ASIN associations that surface weeks later. |
| Verification | 100% scan gate at pack-out; failures reprinted immediately. | A scan gate costs seconds per carton; a gate rejection costs the truck. |
| Version control | Labels printed only from the active shipment plan, never stockpiled across plan revisions. | Mixed-version labels fragment receiving across plans and stall the whole delivery. |
Where to read next
One-line summary
FNSKU per unit, carton ID per box, pallet labels per plan — printed sharp, placed flat, covering everything beneath them, and verified by scanner before anything loads.
Labeling FAQ
Can I use the manufacturer's barcode instead of an FNSKU?
Only if the listing is enrolled for manufacturer-barcode (virtual tracking / commingled) eligibility and the product qualifies — and most experienced sellers decline it anyway: mixing your units with other sellers' identical units means sharing responsibility for their quality problems. Stickered FNSKU tracking is the default recommendation for private-label goods.
Do I really have to cover the old barcode when relabeling?
Yes — fully. A readable barcode under or beside the FNSKU can be scanned by mistake at receiving, mis-associating your unit with the wrong ASIN. The fix is a fully opaque cover label, not a sticker placed at an angle over the code.
What printer spec do I need?
Direct thermal at 300 dpi with genuine-quality label stock produces the crisp, scannable, smudge-proof output that gate scanning requires. 203 dpi printers work for clean flat surfaces but are marginal on curved or textured packaging; inkjet on plain paper under tape is a known scannability failure and should not be used at all.
Where exactly should the carton ID label go?
On a flat surface of the box, not across a seam, edge, or tape line, and never over the FNSKU or another label. For palletized freight, placing the carton ID on more than one face is prudent so receiving can scan boxes without re-stacking.
Want labeling handled at the China hub?
FNSKU application, carton marking and scan-gate verification on every unit — quote your batch and carton spec.
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