Fulfilled by Amazon (FBA) labelling is a genuinely different problem from the courier shipping labels covered in our Amazon Seller Central FBM guide. Rather than printing one label per customer order, FBA involves labelling individual products with a barcode Amazon can scan and track in its own warehouses, plus labelling the boxes and pallets you send inventory in — two label types with different sizes and purposes, both worth understanding before your first shipment.
Product labels: the FNSKU barcode
Every unit you send into FBA generally needs a scannable barcode Amazon can use to identify it inside its fulfilment network — commonly a Fulfilment Network Stock Keeping Unit (FNSKU) barcode, distinct from a product's manufacturer barcode. This label is applied directly to the product or its packaging, not to a shipping box, and is typically a small barcode label rather than anything close to a 4×6 shipping label in size.
Amazon's own labelling service vs applying labels yourself
Amazon offers an optional paid service that applies FNSKU labels to your inventory on arrival at their fulfilment centre, charged per unit. Many sellers instead apply their own product labels before shipping inventory in, particularly once volume makes the per-unit service fee add up — this requires a printer capable of producing correctly sized barcode labels reliably, since a barcode that doesn't scan cleanly can hold up receiving at the fulfilment centre.
Shipment and box labels
Separately from product labels, each shipment you send to Amazon needs box-level labelling — identifying which shipment plan and destination fulfilment centre a given box belongs to, generated through Seller Central's Send to Amazon workflow once you've created a shipment plan. These box labels are generally closer in size to a standard shipping label, and are the part of FBA labelling most similar to the 4×6 format covered in our 4×6 label size guide — worth checking Amazon's current specification for exact size, since it can differ from a standard courier parcel label.
Printer requirements for FBA labelling
Because FBA involves two genuinely different label sizes — small product barcodes and larger shipment box labels — a single thermal printer can usually handle both if it supports the smaller label size, but it's worth confirming your specific printer and driver support the product-label dimensions before assuming your standard 4×6 shipping roll, covered in our thermal printer buying guide, is the correct stock for product labelling too. Some sellers run a separate smaller-format printer specifically for product labels alongside their standard shipping printer.
Common FBA labelling mistakes
The most common issues are barcode quality (a label that scans inconsistently slows down receiving and can result in your shipment being flagged), applying the wrong label to the wrong unit in a mixed-SKU shipment, and confusing product labels with shipment box labels — they serve entirely different purposes and Amazon's systems check for both independently. Double-checking barcode scan quality on a sample of labels before a full shipment print run is worth the few minutes it takes, given how disruptive a receiving hold-up can be to your inventory timeline.
How this differs from selling FBM on the same account
If you sell both FBA and FBM through the same Seller Central account, it's worth keeping the two labelling workflows mentally and physically separate — FBM orders need standard courier shipping labels per customer parcel, covered in our FBM labelling guide, while FBA needs product and shipment labelling for inventory you're sending into Amazon's own warehouses. Mixing up which label goes where between these two very different processes is an easy, avoidable mistake at higher volume.
Frequently asked questions
Can I print FBA product labels on a standard 4x6 thermal printer? A 4x6 thermal printer can print FNSKU product labels if it supports smaller label sizes or roll stock cut to size, but product labels are typically much smaller than a 4x6 shipping label — check Amazon's current label size specification before assuming your existing shipping label roll is the right stock for product labelling too.
Does Amazon apply FNSKU labels for me? Amazon offers an optional FBA Label Service that applies barcodes for a per-item fee, but many sellers apply their own labels before shipment to avoid the cost, particularly at higher volume.
Do I need different labels for FBM and FBA if I sell through both? Yes — FBM orders need standard 4x6 courier shipping labels for individual parcels, while FBA needs product-level FNSKU labels and separate shipment box labels for sending inventory to Amazon's fulfilment centres. They serve completely different purposes and aren't interchangeable.
Built for the parcel side of the business
Our 100 × 150mm direct thermal labels are exactly right for FBM courier parcels and FBA shipment box labels — for FNSKU product labels, check your printer's minimum supported size.
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