Amazon FNSKU Label Requirements in 2026: Size, Placement, Printing, and Scan Compliance

An FNSKU — Fulfillment Network Stock Keeping Unit — is the barcode that ties a physical unit to your seller account inside Amazon’s fulfillment network. If it does not scan, the unit is not reliably yours, and everything downstream of that gets expensive.

Most FNSKU problems are not conceptual. Sellers understand what the label is for. The failures are physical: the label is too small, printed on the wrong device, applied to a curved seam, or sitting next to an uncovered UPC that the scanner reads first.

This is the current specification, why each rule exists, and what changes if you are enrolled in Amazon Transparency. Note that since Amazon ended its FBA labeling service in January 2026, there is no longer a paid fallback at the fulfillment center.

Label size and stock

The minimum accepted size is 1 inch by 2 5/8 inches. In practice most sellers run stock somewhere between 1×2 inches and 2×3 inches, and the larger end of that range is easier to scan reliably on textured or curved packaging.

Both sheet labels and thermal roll formats are accepted. The format matters less than the print method and the finished dimensions.

• Minimum size: 1 inch x 2 5/8 inches.
• Common working range: 1×2 inches to 2×3 inches.
• Roll and sheet stock are both acceptable.
• The label must include the barcode, the FNSKU string, the product title or a condition note as generated by Seller Central, and the condition where applicable.
• Leave adequate quiet zone — white space — on both sides of the barcode. Scanners need it, and trimming it is a common cause of intermittent read failures.

Printing: thermal at 300 DPI, not inkjet

Use a thermal printer at a minimum of 300 DPI. This is the single most consequential specification on the list, and the one most often ignored by sellers scaling out of a home office.

Inkjet output smudges under handling and fades under warehouse lighting and heat. A label has to stay scannable for as long as the inventory sits in the network, which can be many months. A label that scanned perfectly on your desk in March and fails in a fulfillment center in September is functionally the same as no label at all — except that you have already paid to ship it.

Laser is more durable than inkjet but still produces edge-quality problems on small barcodes at low resolutions. Thermal transfer and direct thermal at 300 DPI or above are what production operations use, and the printers themselves are inexpensive relative to a single batch of rejected units.

Placement rules

Placement is where hand-labeling at volume goes wrong, because the correct spot varies by package and operators default to whatever is facing up.

The rule is simple to state and easy to violate: put the barcode on a flat, scannable surface where a handheld scanner can read it in one pass without the operator rotating the unit.

• Apply to a flat face, not across an edge, fold, or corner.
• Avoid seams, especially the sealed seam on a poly bag, where the label will wrinkle.
• Avoid textured, embossed, or heavily coated surfaces that distort bar widths.
• Avoid areas under shrink wrap where glare or wrinkling obscures the code.
• Keep the label flat and fully adhered — a lifted corner catches on equipment and tears.
• Be consistent per SKU so downstream handling and audits are predictable.

Covering manufacturer barcodes

Every other scannable barcode on the unit must be covered. If a UPC or EAN remains readable, a scanner can pick up the wrong identifier, which produces receiving delays, inventory mismatches, and in the worst case commingled inventory problems.

Cover, do not merely overlap. A label placed adjacent to a UPC still leaves the UPC scannable. For products where the manufacturer barcode sits on a curve or a seam and cannot be cleanly covered, a blank cover label first and the FNSKU second is standard practice.

There is one important exception. Amazon Transparency serialization codes are exempt from the cover-all-barcodes rule and must remain visible and scannable alongside the FNSKU.

Transparency codes and combined labels

If your brand is enrolled in Amazon Transparency, each unit carries a unique 2D Data Matrix serialization code in addition to the FNSKU. Once a product is enrolled, anyone listing it must supply a valid Transparency code, which is precisely the point of the program for brand owners.

Amazon publishes several Transparency label layouts, and the guidance encourages sellers toward the types that combine the Transparency code and the product barcode into a single label — commonly Types 3, 4, and 6. Type 4 in particular merges the 2D Data Matrix and the barcode into one layout.

If you use separate labels — Types 1, 2, and 5 — the Transparency code must sit close to the product barcode, and the distance between the two must not exceed 2.5 centimeters. Combined layouts exist largely to remove that measurement as a source of error at volume.

Transparency labeling is per-unit serialized work, which makes it slow and error-prone by hand. It is one of the clearer cases for outsourcing to a labeling operation that already handles serialized application.

What non-compliance costs in 2026

Before 2026 a labeling mistake had a paid escape hatch: Amazon would apply the label for roughly $0.55 per unit. That option no longer exists. Units arriving without compliant labels are received as an inbound defect and billed at unplanned service rates, historically $0.20 to $2.00 per unit depending on size tier.

Beyond the fee, non-compliant units can be delayed at check-in or held as stranded inventory, and prep defects can affect reimbursement eligibility if units are later lost or damaged. Amazon’s requirements change; verify current specifications in Seller Central before each inbound plan.

We apply FNSKU labels, box labels, and Transparency codes to Amazon specification at our Jamaica, NY warehouse, with free receiving and two weeks of storage on every inbound shipment. See labeling rates or send your SKU list for a written quote.