Barcodes for Amazon FBA: Requirements, FNSKU, and How to Get Started

Amazon FBA (Fulfillment by Amazon) requires two types of barcodes: a GS1-registered UPC-A or EAN-13 barcode to create your product listing, and an FNSKU (Fulfillment Network Stock Keeping Unit) barcode to track your specific inventory in Amazon's warehouses. Amazon hosts over 2 million active third-party sellers, according to Marketplace Pulse, and its automated GTIN verification system increasingly checks barcodes against the GS1 database. Getting your barcodes right prevents listing suspensions, inventory commingling problems, and delayed product launches.

The Two Barcodes You Need

1. Product Barcode (UPC-A or EAN-13) — For Your Listing

Every product listed on Amazon needs a Global Trade Item Number (GTIN) — the number encoded in a UPC-A or EAN-13 barcode. This number identifies what the product is across all of retail, not just Amazon.

Amazon uses the GTIN to:

• Create your product detail page
• Match your product to the existing Amazon catalog (if the product already exists)
• Verify your product against the GS1 database (Brand Registry enrollees)
• Enable barcode-based product search on Amazon

Where to get it: Register with GS1 and obtain a company prefix. See our complete guide to getting a barcode for your product.

Which format: UPC-A if registered with GS1 US (12 digits), or EAN-13 if registered with any other GS1 organization (13 digits). Amazon accepts both interchangeably — they store GTINs in 14-digit GTIN-14 format internally.

2. FNSKU Barcode — For FBA Warehouses

FNSKU (Fulfillment Network Stock Keeping Unit) is Amazon's internal barcode that links inventory to your specific seller account. It's a Code 128 barcode printed on a label you apply to each unit before shipping to Amazon's fulfillment centers.

Why FNSKU matters: Imagine three different sellers all ship the same product (same UPC) to Amazon's warehouse. Without FNSKU, Amazon treats all units as interchangeable — a customer who orders from you might receive a unit sent by another seller. If that other seller ships counterfeits or damaged goods, you get the complaint.

FNSKU solves this by tagging each unit to a specific seller account. Amazon's warehouse associates scan the FNSKU to confirm which seller's inventory they're handling.

Where to get it: Amazon generates your FNSKU automatically when you create an FBA listing. Download the barcode labels from Seller Central under "Manage FBA Inventory" → "Print item labels."

Amazon Barcode Requirements

GS1 Registration

Amazon has progressively tightened barcode requirements. The current state:

Brand Registry members: Amazon verifies your GTIN against the GS1 database. The GS1 prefix owner must match the brand owner on your Amazon account. Mismatches result in listing suppression.

Non-Brand Registry sellers: Amazon still accepts UPC/EAN codes for listing creation, but verification is increasingly automated. Products in restricted categories or those flagged by Amazon's catalog quality team require GS1 verification.

GTIN Exemption: Some categories allow listing without a GTIN (handmade, private label in certain categories). Apply through Seller Central if your product genuinely doesn't have a GTIN. This exemption is separate from the barcode requirement for FBA labeling.

FBA Labeling Options

When sending inventory to Amazon FBA, you have three labeling choices:

Option 1: FNSKU Labels (Recommended)

Apply FNSKU barcode labels to each unit. This is the safest approach:

• Your inventory is tracked separately from other sellers
• No commingling risk
• Required for products without a manufacturer barcode or for private label products

Label specifications:

• Barcode format: Code 128
• Label size: 1" x 2" or 1" x 3" (Amazon standard)
• Must cover any existing scannable barcodes on the packaging (to prevent mis-scanning)
• Print on white adhesive labels with black barcode — thermal transfer recommended for durability

Option 2: Manufacturer Barcode (Stickerless Commingled)

If your product has a UPC/EAN barcode on the manufacturer packaging, you can opt into stickerless commingled inventory. Amazon uses the manufacturer barcode instead of FNSKU.

Risk: Your inventory gets commingled with other sellers' units of the same product. If another seller sends counterfeits or damaged goods with the same UPC, those units may be shipped to your customers. Not recommended for private label brands or high-value products.

Option 3: Amazon Barcode Service

Pay Amazon to apply FNSKU labels for you at the fulfillment center. Costs $0.55 per unit (as of 2026). Convenient if you can't label products yourself, but adds cost at scale.

Step-by-Step: Setting Up Barcodes for Amazon FBA

Step 1: Get Your UPC/EAN Codes

1. Register with GS1 US (or your local GS1 organization)
2. Choose a company prefix size based on how many products you'll sell
3. Assign product numbers to each unique item (every size, color, and variant needs its own number)
4. Generate UPC-A barcodes for your product packaging

Cost: GS1 US initial fee starts at ~$250 for 10 product codes + $50/year renewal.

Step 2: Create Your Amazon Listing

1. Log into Seller Central
2. Add a new product using your UPC or EAN code
3. If the product exists in Amazon's catalog, match to the existing listing
4. If it's a new product, create a new listing with your product details
5. Set up FBA and select your labeling preference

Step 3: Generate FNSKU Labels

1. In Seller Central, go to Manage FBA Inventory
2. Select your products and choose "Print item labels"
3. Choose label size and quantity
4. Download the PDF with FNSKU barcode labels
5. Print on compatible label sheets (Avery 5160 or equivalent for 1" x 2-5/8" labels)

Step 4: Label Your Products

1. Print FNSKU labels using a thermal or laser printer
2. Apply one FNSKU label to each individual unit
3. Cover any existing manufacturer barcodes that might confuse Amazon's scanners
4. Ensure the barcode is on a flat surface, not wrapping around edges or covering product information

Step 5: Ship to Amazon

1. Create a shipping plan in Seller Central
2. Amazon assigns fulfillment centers for your inventory
3. Print box-level labels (Amazon provides these — FBA box ID labels)
4. Ship to the designated fulfillment centers

Common Barcode Problems on Amazon

"GTIN Not Found" or Listing Suppressed

Cause: Amazon can't verify your UPC/EAN against the GS1 database, or the prefix owner doesn't match your brand.

Fix:

• Verify your GS1 registration is active (annual renewal paid)
• Ensure the brand name on your GS1 account matches your Amazon Brand Registry
• Upload your GS1 certificate to Amazon when requested
• If you used a reseller barcode, you'll likely need to register with GS1 and get legitimate codes

Commingled Inventory Issues

Cause: Customer receives a counterfeit or different-condition unit because commingled inventory mixed your units with another seller's.

Fix:

• Switch to FNSKU labeling immediately
• Disable commingled inventory in your FBA settings
• For existing commingled inventory, create a removal order and re-send with FNSKU labels

Barcode Won't Scan at Amazon Warehouse

Cause: Poor print quality, barcode too small, insufficient quiet zones, or label placed on a curved surface.

Fix:

• Print at 300 DPI minimum
• Use thermal transfer printing for best quality
• Ensure labels are at least 1" x 2" with adequate quiet zones
• Place on flat packaging surfaces
• Test scanning before shipping — use our free barcode scanner to verify readability

Multiple Barcodes Confusing Scanners

Cause: Amazon's warehouse scanners read the wrong barcode on your packaging — the manufacturer UPC instead of the FNSKU, or a barcode from a different product.

Fix: Cover all barcodes except the FNSKU with opaque labels or stickers. Only one scannable barcode should be visible on each unit.

Amazon Transparency Program

Amazon's Transparency program adds a third barcode layer for brand protection. Enrolled brands receive unique Transparency codes — 2D barcodes with serialized identifiers — that are applied to each unit.

How it works:

1. Brand enrolls in Transparency through Amazon
2. Amazon provides unique serialized codes (one per unit)
3. Brand applies Transparency barcode labels to every unit manufactured
4. Amazon scans the Transparency code at the fulfillment center
5. Units without valid Transparency codes are rejected — blocking counterfeits

Transparency vs. FNSKU: Transparency is about brand protection (authentication). FNSKU is about inventory tracking (which seller owns which units). Products can carry both.

Cost: Amazon charges per Transparency code label (pricing varies, typically $0.01-0.05 per unit depending on volume).

Cost Summary

Generate your product barcodes free using our UPC-A generator or EAN-13 generator. For Code 128 labels (internal use, shipping), use our Code 128 generator.