FNSKU label specification
Most guides to FNSKU labels repeat the same three sentences. This page collects what Amazon actually publishes — every supported label size, the printing rules, where the label may sit — and says plainly where Amazon documents nothing at all.
An FNSKU label is the sticker that ties a physical unit to your offer inside an Amazon fulfilment centre. Since 1 January 2026 Amazon no longer applies it for you in the US store, so getting it right is now your problem rather than a paid service.
What has to be on the label
Amazon's own labelling guide lists exactly three data fields:
| Field | What it is |
|---|---|
| FNSKU | The identifier fulfilment centres use to recognise the offer, printed as a barcode and as readable text |
| Name | The product name |
| Condition | A description of the item's condition — in practice New or Used |
Two things worth knowing, because almost every other guide states them as fact. Amazon's published documentation never names the barcode symbology for FNSKU labels; tools, including this one, use Code 128, which is the established practice rather than a documented requirement. And Amazon publishes no character limit for the product name — long titles simply get cut off, which is cosmetic, because the barcode is what gets scanned.
Every label size Amazon supports
Amazon's label generator offers eleven sheet formats. Only one of them is US Letter; the rest are A4. Where a standard Avery die matches exactly, it is named.
| Labels per page | Label size | Sheet | Avery equivalent |
|---|---|---|---|
| 30 | 1" × 2 5/8" (25.4 × 66.7 mm) | US Letter | 5160 · 8160 |
| 21 | 63.5 × 38.1 mm (2.50" × 1.50") | A4 | L7160 |
| 24 | 63.5 × 33.9 mm | A4 | L7159 |
| 24 | 64.6 × 33.8 mm | A4 | — |
| 24 | 66.0 × 33.9 mm | A4 | — |
| 24 | 70.0 × 36.0 mm | A4 | — |
| 24 | 70.0 × 37.0 mm | A4 | — |
| 24 | 63.5 × 38.1 mm | A4 | — |
| 27 | 63.5 × 29.6 mm | A4 | — |
| 40 | 52.5 × 29.7 mm | A4 | — |
| 44 | 48.5 × 25.4 mm | A4 | — |
A warning that saves a wasted pack: Avery 5163 is not one of these. It is 2" × 4", ten labels per sheet, and matches no Amazon format — despite being suggested for FBA in plenty of forum posts.
Thermal roll sizes are a different story. Rolls sold as “FNSKU labels” in 2-1/4" × 1-1/4" and 2" × 1" work fine in practice, but Amazon's own documentation lists sheet formats only — there is no published roll specification to comply with.
Printing
This is where Amazon is specific, and where most unscannable labels come from:
| Rule | Detail |
|---|---|
| Printer | Direct thermal or laser. Never inkjet — Amazon cites smearing and blurring that make labels unreadable |
| Resolution | 300 DPI or greater |
| Ink and stock | Black ink on non-reflective paper with adhesive backing |
| Scaling | Print at 100%. “Fit to page” shrinks the barcode and is a common cause of scan failures |
| Copies | Photocopied or damaged labels are not accepted |
| Adhesive | Removable adhesive is recommended, not required — the Avery sheets Amazon's own formats map to are permanent |
Amazon publishes no minimum bar width and no quiet-zone figure for these labels. The quiet zone that matters comes from the symbology itself: Code 128 expects a clear margin of at least ten times the narrow-bar width on each side. Leave the white space; do not crop tight to the bars.
Where the label may sit
Placement rules are short and strictly enforced by the scanner, if not by a human:
| Rule | Why |
|---|---|
| Cover every other barcode | The manufacturer's UPC, EAN, JAN or ISBN must be completely covered. Two scannable barcodes is the classic cause of lost inventory |
| 0.25" from the edge | Amazon asks for a quarter-inch between the label and the edge of the packaging |
| Flat surfaces only | No corners, edges or curves — a label bent around a curve will not scan |
| Outside the prep material | If the unit is polybagged or shrink-wrapped, the label goes on the outside, not inside |
What changed in 2026
Two separate changes, with two different dates, are constantly confused with each other.
1 January 2026 — prep and item labelling ended in the US store. Amazon stopped offering the service: units must arrive already prepped and labelled. Shipments created before that date were still covered, even if the inventory arrived later. Units that turn up unlabelled or with defective labels are not eligible for reimbursement if they are lost or damaged, and the defects show up in the Inbound Performance Dashboard.
31 March 2026 — commingled inventory ends. This one moves in the opposite direction depending on who you are. Brand owners enrolled in Brand Registry no longer need FNSKU stickers on products that already carry a manufacturer barcode. Resellers who are not brand owners are now required to use them, even on products that have a UPC or EAN. Products with no manufacturer barcode need an FNSKU either way.
Why labels get rejected
Amazon's own list of the common errors is blunt and short: a missing barcode label, a mislabelled item, a barcode that cannot be scanned, and preparation errors. Every one of those traces back to something on this page — an inkjet print, a scaled page, a label bent around a corner, or an old barcode left showing.
Amazon suggests testing your own output periodically with a tethered scanner. It is worth doing before a five-hundred-unit run rather than after.