The Ultimate Guide to Amazon FNSKU Labeling Compliance (2026 Update)
One of the most common reasons for stranded inventory in 2026 is incorrect labeling. Amazon requires strict adherence to barcode standards. This guide explains when to use a Manufacturer Barcode (UPC) and when an Amazon Barcode (FNSKU) is mandatory.
1) What is an FNSKU?
FNSKU stands for Fulfillment Network Stock Keeping Unit. It is a unique identifier that links a product to your specific seller account. Unlike a UPC, which can be shared across sellers, FNSKU ensures that when a customer buys from you they receive your exact unit.
2) The dangers of commingling (UPC)
Amazon still allows eligible products to use manufacturer barcodes (commingled inventory), but this increases risk. If another seller sends counterfeit or low-quality units for the same UPC, customer complaints can still impact your account.
3) Labeling Requirements Checklist
Make sure every unit you send to Stratosphere Prep or directly to Amazon follows these rules:
- Cover the UPC: The FNSKU label must fully cover the original barcode.
- White Space: Keep at least 0.25 inches of clear space on both sides of the barcode.
- Readability: Use white, non-reflective label stock for high scan reliability.
- Text: Label should include ASIN, item name, and condition (New/Used).
4) Recommended Thermal Printers
Inkjet labels smear and fade. Thermal printers are the standard for FBA.
| Printer Model | Best Use Case | Approx Price |
|---|---|---|
| Rollo USB/Wireless | High-volume 4x6 shipping labels | $180-$250 |
| DYMO LabelWriter 4XL | FNSKU item labels and small batch workflows | $200-$280 |
| Zebra GK420d | Warehouse-level reliability and speed | $400+ |
5) Common Labeling Mistakes
Frequent errors include placing labels around package corners, printing faded barcodes, and covering expiration dates or product-critical information.
Tired of labeling thousands of units?
Stratosphere Prep uses industrial Zebra printers to apply FNSKU labels with high scan accuracy, so you can focus on sourcing and growth.
Get a Prep QuoteFAQ
Can I print FNSKU labels on regular paper?
Technically yes, but peel quality and barcode reliability are lower. Thermal labels are the recommended standard.
Does Stratosphere Prep charge extra for label removal?
If existing stickers must be removed before relabeling, a small add-on fee may apply depending on unit condition and quantity.