Selling on Amazon means dealing with barcodes.

Barcodes help Amazon track inventory, prevent counterfeits, and ensure smooth order fulfillment. But with different codes like UPC, FNSKU, ASIN, SKU, and even the Transparency Code, sellers often get confused.

This guide will break down everything you need to know—how to get the right barcode, when to use it, and how to avoid common barcode-related issues.

What Are Amazon Barcodes and Why Do You Need Them?

A barcode is a unique identifier assigned to a product. It allows Amazon’s system to recognize, categorize, and track the item through its fulfillment network.

Without the right barcode, your listing might not go live, your inventory could get lost, or worse—your account could face suspension.

There are two main barcode types Amazon recognizes:

  1. Manufacturer Barcodes (Global Trade Item Number or GTIN, such as UPC, EAN, or ISBN)
  2. Amazon Barcodes (FNSKU, Transparency Codes, etc.)

Each serves a specific purpose, and using the wrong one can cause inventory mix-ups, lost shipments, and listing errors.

Understanding GTINs: UPC, EAN, ISBN, and JAN

The Global Trade Item Number (GTIN) is a universal product identification system. It ensures that every product has a unique identifier, helping retailers and marketplaces track items correctly.

Here’s a breakdown of GTINs:

GTIN TypeDigitsUsed In
UPC (Universal Product Code)12USA & Canada
EAN (European Article Number)13Europe & International
ISBN (International Standard Book Number)10 or 13Books
JAN (Japanese Article Number)13Japan

Amazon requires a GTIN for most new listings unless you apply for a GTIN exemption.

How to Get a UPC for Amazon?

Amazon verifies UPC numbers against GS1, the official provider. If you purchase from third-party resellers, your barcode might be rejected.

  • Visit GS1.org to register.
  • Buy a company prefix and generate your unique UPCs.
  • Each product variation (size, color, pack) needs a separate UPC.

⚠ Warning: Many sellers try buying cheap UPCs from unauthorized sellers. But Amazon cross-checks UPCs with GS1. If they don’t match your brand, your listing may get flagged.

FNSKU: Amazon’s Internal Barcode for FBA Sellers

FNSKU (Fulfillment Network Stock Keeping Unit) is Amazon’s barcode for FBA sellers. It’s how Amazon differentiates your inventory from other sellers’.

Why Use FNSKU Instead of a UPC?

If you send inventory to an Amazon warehouse with only a UPC, Amazon might mix your units with other sellers’ products. This can lead to customer complaints, fake product claims, or even account suspensions.

With an FNSKU, Amazon tracks only your products under your seller account.

How to Get an FNSKU?

  1. Create a new listing in Seller Central.
  2. Choose “Amazon Barcode” instead of the manufacturer barcode.
  3. Amazon assigns an FNSKU for that product.
  4. Download and print the label to attach it to each unit.

If you sell private-label products, always use an FNSKU instead of a UPC.

ASIN, SKU, and Transparency Codes: What’s the Difference?

  • ASIN (Amazon Standard Identification Number): A 10-character unique code Amazon assigns to every product in its catalog. You don’t need to create one—Amazon generates it automatically when you list a product.
  • SKU (Stock Keeping Unit): A seller-defined code used for tracking inventory internally. It’s helpful for managing multiple variations or warehouses.
  • Transparency Code: A QR-code-based anti-counterfeit label for brand-registered sellers.

For brand protection and counterfeit prevention, Amazon encourages brands to join the Transparency Program. If you’re a growing private-label seller, ZonHack can help you navigate Amazon’s brand protection tools and keep your business safe.

Printing and Applying Barcodes Correctly

Amazon has strict rules for barcode labels. If your labels are missing or damaged, Amazon may reject your inventory or charge a relabeling fee.

How to Print FNSKU Barcodes?

  1. Go to Inventory > Manage FBA Shipments in Seller Central.
  2. Select your product and download the FNSKU label PDF.
  3. Use a thermal printer for best quality (Amazon recommends 300 dpi).
  4. Labels must be at least 1×2 inches in size.

Placement Guidelines:

  • Place the label on a flat surface so it’s easy to scan.
  • Ensure no folds, wrinkles, or smudges obscure the barcode.
  • Do not place labels over seams or box edges.
  • Cover any existing UPC if you are using an FNSKU.

If applying labels manually sounds like a hassle, ZonHack’s FBA Prep Service can help handle barcode labeling, packaging, and compliance to avoid issues with Amazon.

GTIN Exemptions: Can You List Without a UPC?

Some sellers can list products without a UPC or EAN through a GTIN exemption.

Who Qualifies for GTIN Exemption?

  • Private-label sellers with their own branded products.
  • Handmade or custom products that don’t have a barcode.
  • Sellers listing products in restricted categories (e.g., certain apparel, accessories, or crafts).

How to Apply for GTIN Exemption?

  1. Go to Seller Central > Apply for GTIN Exemption.
  2. Select your category and brand name.
  3. Upload images proving your product doesn’t have a UPC (must show branding or logo).
  4. Submit and wait for Amazon’s approval (usually 24-48 hours).

⚠ Important: If you’re building a long-term brand, it’s better to register your UPCs through GS1 instead of relying on GTIN exemption. Amazon frequently changes policies, and exemptions aren’t guaranteed forever.

Bottom Line: Best Practices for Amazon Barcodes

  1. Buy UPCs only from GS1. Avoid resellers to prevent listing rejections.
  2. Use FNSKU for FBA products. This ensures your inventory isn’t mixed with others.
  3. Label products properly. Poor labels cause delays and extra fees.
  4. Consider GTIN exemption wisely. If you plan to scale, invest in proper barcodes.

Understanding Amazon’s barcode system saves you time, prevents costly mistakes, and ensures smooth selling.

Need help managing barcodes, listing approvals, or FBA compliance? ZonHack provides expert Amazon solutions for sellers looking to grow their business efficiently.

Stay ahead—contact ZonHack today!

Frequently Asked Questions About Amazon Barcodes

1. Can I Sell on Amazon Without a Barcode?

Yes, but only if you qualify for a GTIN exemption. Amazon requires most products to have a barcode (UPC, EAN, or ISBN). However, handmade items, private-label goods, and certain categories may be eligible for listing without a barcode. You must apply for GTIN exemption through Seller Central and provide proof of your brand or product uniqueness.

2. What Happens If I Use a Third-Party UPC?

If your UPC doesn’t match GS1 records, Amazon may flag your listing, remove it, or suspend your account. Many sellers try to save money by purchasing cheap UPCs from resellers, but Amazon’s system cross-checks UPC ownership with GS1. If your brand name doesn’t match GS1’s database, your listing could be rejected.

3. Is an FNSKU Required for Every FBA Product?

Yes, if you choose Amazon’s barcode system instead of the manufacturer’s. FNSKUs are recommended for private-label sellers because they prevent inventory mix-ups. Without an FNSKU, Amazon may commingle your stock with other sellers’ identical products, which increases the risk of counterfeit claims.

4. How Do I Fix the “Invalid UPC” Error on Amazon?

This error usually happens when Amazon detects a non-GS1 UPC. To fix it:

  • Ensure you bought the UPC from GS1.org.
  • Double-check that the UPC is correctly entered when creating the listing.
  • If you have brand registry, try applying for a GTIN exemption instead.

5. How Can I Protect My Brand from Counterfeiters Using Barcodes?

Amazon offers Transparency Codes, which are unique QR codes that help verify the authenticity of your products. If you’re a brand-registered seller, you can enroll in Amazon’s Transparency Program to ensure only legitimate units are sold. ZonHack helps sellers navigate Amazon’s brand protection tools, from Transparency to Project Zero and Brand Registry.

6. What If Amazon Rejects My Inventory Due to Barcode Issues?

Barcode-related rejections usually happen due to:

  • Low-quality barcode printing (smudged, faded, or poorly placed labels).
  • Incorrect label placement (over seams, wrapped around curves).
  • Mismatched UPC and ASIN (listing issues).

To avoid problems, always use high-quality labels and follow Amazon’s barcode placement guidelines.