FNSKU Labels: Size, Placement and Amazon's Requirements
The label sizes Amazon accepts, where the label goes on your product, how to print it from Seller Central, and what happens when a label is wrong.
Every FNSKU label you stick on a product decides whether that unit checks in at Amazon or gets flagged as a defect. Since March 31, 2026, resellers must put an FNSKU label on every unit they send to FBA, so FNSKU labeling is now part of almost every shipment. This guide covers Amazon's own label requirements: the sizes, the printers, where the label goes on your product, and how to print labels in Seller Central, step by step.
What is an FNSKU label?
An FNSKU label is the barcode sticker Amazon uses to track your units inside its fulfillment centers. FNSKU is short for Fulfillment Network Stock Keeping Unit. The label shows an Amazon barcode that starts with X (or the ASIN), the product name and its condition, and it goes on every unit you send to FBA.
X00EXAMPLE
Stainless Steel Water Bottle, 32 oz, Blue
New
Amazon checks that a printed label matches the label Seller Central generates. It has to include the ASIN or FNSKU, the product name and the item condition, with white space around the barcode and around the label's edges: 0.25 inch on the sides and 0.125 inch on the top and bottom. Each FNSKU belongs to one product in one condition, so every size, color and condition you sell gets its own label. For how an FNSKU is created in your account, read what Amazon FNSKU is and how to create one.
Who needs FNSKU labels in 2026
On March 31, 2026, Amazon ended commingling and changed its barcode rules. Resellers, authorized resellers included, must label every unit with an Amazon barcode even when it already has a manufacturer barcode; units that arrive without one are treated as defective. Brand owners with the Brand Representative role in Amazon Brand Registry can track eligible products by their manufacturer barcode with no sticker. A product with no manufacturer barcode, or with a GTIN exemption, needs an FNSKU label whoever sells it. Amazon's barcode change FAQ has the details.
Are FNSKU and SKU the same?
No. A SKU is the code you create to track a product in your own catalog, and it can be anything you choose. An FNSKU is the code Amazon assigns to your offer for Fulfillment by Amazon, so its warehouses can tell your units apart from another seller's units of the same product.
The four codes sellers mix up, and who creates each one:
| Code | Created by | What it identifies |
|---|---|---|
| SKU | You | Your own code for a product in your catalog. Any letters and numbers you choose. |
| FNSKU | Amazon | Amazon's code for your offer in its fulfillment network. Printed on the FNSKU label; it starts with X. |
| ASIN | Amazon | Amazon's code for the product itself in its catalog. Every seller of that product shares it. |
| UPC, EAN or ISBN | The manufacturer | The manufacturer barcode printed on the packaging. |
What size is an FNSKU label?
Amazon accepts FNSKU labels from 1 x 2 inches up to 2 x 3 inches, such as 1 x 3 or 2 x 2 inches. They must be printed in black on white, non-reflective labels with removable adhesive. On US letter paper, Seller Central prints 30 labels per sheet, each 1 x 2 5/8 inches.
The label sizes Seller Central formats for, from Amazon's label paper requirements:
| Format | Label size |
|---|---|
| Thermal labels (one per label) | Any size from 1 x 2 inches to 2 x 3 inches |
| 30 labels per page | 1 inch x 2 5/8 inches on US letter |
| 21 labels per page | 63.5 mm x 38.1 mm on A4 |
| 24 labels per page | 63.5 mm x 33.9 mm, 63.5 mm x 38.1 mm, 64.6 mm x 33.8 mm, 66.0 mm x 33.9 mm, 70.0 mm x 36.0 mm or 70.0 mm x 37.0 mm on A4 |
| 27 labels per page | 63.5 mm x 29.6 mm on A4 |
| 40 labels per page | 52.5 mm x 29.7 mm on A4 |
| 44 labels per page | 48.5 mm x 25.4 mm on A4 |
Printer requirements
- Use a thermal printer (Seller Central's tools are built for them) or a laser printer. Amazon says not to use inkjet printers.
- Print at 300 dots per inch or more. Each label has to stay readable and scannable for 24 months.
- Test printed labels by scanning them, and clean or replace print heads from time to time.
- Set printer scaling to None or 100% when printing a PDF sheet, or the barcode prints at the wrong size.
Where to Put the FNSKU Label on Your Product
Amazon's label placement requirements, in order:
- Put the correct label on each item: the FNSKU for that exact product and condition.
- Cover every other visible barcode, except serial number barcodes and Transparency authentication labels.
- Place the label on a flat side, never on a curve or a corner of the package.
- Leave at least 0.25 inch between the edge of the label and the edge of the packaging.
- Make sure the barcode still scans after prep, such as through a poly bag or bubble wrap.
- In a case pack, label every item inside and remove any barcodes on the case itself.
Products sold as a set also need a “Sold as set” label so the units are not separated, and poly bags with an opening of 5 inches or more need a suffocation warning. Both rules are in Amazon's packaging requirements.
How do I print Amazon FNSKU labels?
Print FNSKU labels from Seller Central. In the Send to Amazon workflow, click Print SKU labels next to each SKU that needs an Amazon barcode, or select products in Manage Inventory and choose Print item labels. Pick the thermal format or the sheet size that matches your labels, print at 100% scale, then label each unit.
- 1
Open the SKUs that need labels
Start or open a shipment in the Send to Amazon workflow. Each SKU that needs an Amazon barcode shows Print SKU labels in its Information/action column. Outside a shipment, go to Manage Inventory and select the products instead.
- 2
Print the labels
Click Print SKU labels for one SKU, or Print all SKU labels at the end of step 1 for the whole shipment. From Manage Inventory, choose Print item labels in the Select group action menu.
- 3
Choose the label format
Pick the thermal printing format for a thermal printer, or the standard sheet size that matches your label paper for a laser printer, such as 30 labels per US letter sheet.
- 4
Print at full size
Set the printer's scaling to None or 100% so the barcode prints at its real size, in black on white, non-reflective labels with removable adhesive.
- 5
Scan a test label
Scan one printed label before you print the batch, and keep testing as you go so smudged or faded labels never reach a box.
- 6
Label each unit
Stick one label on each unit on a flat side, at least 0.25 inch from the edge, covering any other visible barcode. Every unit in a case pack gets its own label.
Or have Ecom Circles label them.
Send your inventory to our warehouse and we print and apply the FNSKU labels, then ship the units to FBA. For prep clients, products that only need the FNSKU label are $1.00 per unit. Full FBA prep runs from $1.50 down to $0.85 per unit by monthly volume.
What Happens When an FNSKU Label Is Wrong
If a unit that needs an Amazon barcode arrives without one, Amazon marks it as defective, applies a barcode sticker itself and reports the defect on your Inbound Performance Dashboard. Units that are not labeled to Amazon's rules are not eligible for reimbursement, and missing Amazon's prep requirements can lead to refused inventory, blocked shipments or charges for prep and noncompliance. Amazon also offers its own FBA Label Service, which prints and applies the labels for a per-item fee. These are the label problems Amazon lists:
| Problem | What it means |
|---|---|
| Barcode missing | The item arrived without a proper barcode. |
| Unit mislabeled | The item arrived with a barcode that does not match the physical product. |
| Barcode cannot be scanned | The label was smudged, placed around a corner or curve, or printed on a reflective surface. |
| Unit or shipment preparation errors | Items arrived with labeling, packaging and prep, or shipping requirement errors. |
FNSKU Labeling Service from Ecom Circles
Labeling hundreds of units by hand is slow, and one wrong label sends a unit to the defect report. Ecom Circles receives your inventory at our warehouses in the Chicago area and Atlanta, checks each delivery, prints and applies the FNSKU labels to Amazon's rules and ships the units into FBA. Products that only need the FNSKU label are $1.00 per unit for prep clients. When a product also needs poly bagging or other prep, FBA prep runs from $1.50 down to $0.85 per unit by monthly volume, and the same warehouse preps Walmart WFS shipments. Prep runs through your Ecom Circles account on the Growth plan or higher. To compare providers first, read our FBA prep center guide.
See FBA prep and labeling pricesFNSKU Label FAQ
What is an FNSKU label?
An FNSKU label is the barcode sticker Amazon uses to track your units inside its fulfillment centers. FNSKU is short for Fulfillment Network Stock Keeping Unit. The label shows an Amazon barcode that starts with X (or the ASIN), the product name and its condition, and it goes on every unit you send to FBA.
Are FNSKU and SKU the same?
No. A SKU is the code you create to track a product in your own catalog, and it can be anything you choose. An FNSKU is the code Amazon assigns to your offer for Fulfillment by Amazon, so its warehouses can tell your units apart from another seller's units of the same product.
What size is an FNSKU label?
Amazon accepts FNSKU labels from 1 x 2 inches up to 2 x 3 inches, such as 1 x 3 or 2 x 2 inches. They must be printed in black on white, non-reflective labels with removable adhesive. On US letter paper, Seller Central prints 30 labels per sheet, each 1 x 2 5/8 inches.
How do I print Amazon FNSKU labels?
Print FNSKU labels from Seller Central. In the Send to Amazon workflow, click Print SKU labels next to each SKU that needs an Amazon barcode, or select products in Manage Inventory and choose Print item labels. Pick the thermal format or the sheet size that matches your labels, print at 100% scale, then label each unit.
Where do you put the FNSKU label on a product?
Put the FNSKU label on a flat side of the product, never on a curve or a corner, with at least 0.25 inch between the label and the edge of the packaging. Cover every other visible barcode except serial number and Transparency labels, and make sure the label still scans through any poly bag.
Do I need an FNSKU label if my product already has a UPC?
Usually yes. Since March 31, 2026, resellers must put Amazon barcodes on every unit, even when the product has a manufacturer barcode. Brand owners with the Brand Representative role in Amazon Brand Registry can skip the sticker for products in new condition with a single scannable UPC, EAN or ISBN that matches one ASIN.
Can I print FNSKU labels on an inkjet printer?
No. Amazon asks for a thermal or laser printer and says not to use inkjet printers for Amazon barcodes. Each label has to stay readable and scannable for 24 months, so Amazon recommends a print resolution of 300 dots per inch or more and scanning a test label from time to time.