EAN Barcodes: How to Label Your Inventory for Marketplaces and 3PLs

EAN barcodes are the standard 13-digit European Article Numbers used to uniquely identify retail products across physical and digital storefronts. If you are selling online, these barcodes serve as a global passport for your inventory, ensuring that your items are accurately tracked from the manufacturer to the customer. When setting up your fulfilment in Europe, understanding how these identifiers work is critical to preventing lost stock and shipping errors.

Failing to prepare your inventory with the correct barcodes can lead to delayed shipments, expensive warehouse fees, and even account suspension on major platforms. This article clarifies the relationship between different barcode types, explains why modern warehouses rely on them, and shows how to prepare your stock for smooth operations.

What is a GTIN and how does it relate to EAN barcodes?

Every physical product sold in modern retail requires a unique identifier to prevent confusion in the supply chain. The universal term for this identifier is a GTIN, which stands for Global Trade Item Number. A GTIN is not a physical barcode itself, but rather the unique number sequence represented by the black lines of a barcode.

Depending on where you sell, your GTIN will take different forms. In North America, the standard is the 12-digit Universal Product Code (UPC). In Europe and most other parts of the world, the standard is the 13-digit European Article Number, commonly known as the EAN. Therefore, when people ask what is a GTIN, the answer is that it is the global standard family of numbers, and an EAN is simply the specific 13-digit version used in European retail.

The number sequence is structured systematically. It begins with a country prefix assigned by GS1, the global standards organisation. This is followed by a company prefix that uniquely identifies your brand, a unique item reference number that you assign to the specific product, and a final check digit calculated from the preceding numbers to ensure the barcode scans correctly. This structured approach ensures that no two products in the world share the exact same code.

Why marketplaces require GS1 barcodes

As online shopping has grown, major ecommerce platforms have standardised their databases to maintain order and security. Using GS1 barcodes for marketplaces is now a mandatory requirement on platforms such as Amazon, eBay, and many European marketplaces like Bol, Allegro, and Cdiscount.

In the early days of ecommerce, sellers could purchase cheap barcodes from unverified third-party resellers. These resold numbers were often recycled or hijacked from other brands, leading to massive data conflicts. Two completely different items, such as a leather wallet and a bottle of vitamins, would end up sharing the same barcode, causing chaos in marketplace databases and search results.

To solve this, marketplaces now integrate directly with the GS1 database. When you list a new product, the marketplace automatically checks the barcode prefix against GS1 records to verify that the brand name matches the registered owner of the barcode. If there is a mismatch, the listing will be rejected, or your seller account may be suspended. Obtaining your barcodes directly from the official GS1 registry is the only way to guarantee your listings remain active and protected from hijacking.

FNSKU vs EAN: Understanding marketplace labels

When managing inventory, it is easy to get confused by the different codes printed on product packaging. Sellers often ask about the differences between an FNSKU vs EAN, and how these codes relate to a standard warehouse SKU.

An EAN is a globally recognised barcode that remains the same regardless of where the product is sold. An FNSKU, or Fulfilment Network Stock Keeping Unit, is unique to Amazon. Amazon uses FNSKUs to track inventory within its own fulfilment centres. If multiple sellers are offering the same product under the same EAN, Amazon uses the FNSKU to identify which specific unit belongs to which seller. This prevents your inventory from being mixed, or commingled, with potentially counterfeit units from another seller.

A warehouse SKU is different again. A SKU, or Stock Keeping Unit, is an alphanumeric code that you create to identify your products internally. For example, a red medium t-shirt might have the SKU "TSHIRT-RED-MED". SKUs are used for inventory tracking in your own systems and your partner systems. While a SKU is a text label, an EAN is the physical barcode that translates that product identity into a scannable format that any system can read.

Do I need barcodes for a 3PL?

A common question for growing brands is: do I need barcodes for a 3PL? The short answer is yes. While some traditional warehouses might manage inventory manually, modern third-party logistics providers rely entirely on barcode scanning to maintain efficiency and accuracy.

When your stock arrives at a 3PL warehouse, the receiving team must scan each item to log it into the warehouse management system. During the picking process, warehouse staff use handheld mobile computers to scan the barcode of every item they place in a shipping box. This digital verification ensures that the picker has selected the correct size, colour, or flavour of a product.

Without a unique barcode on every sellable variant, the risk of picking errors rises dramatically. If a warehouse has to rely on manual visual checks to tell the difference between a dark blue t-shirt and a black t-shirt, mistakes will happen. These mistakes result in costly customer returns, negative reviews, and additional shipping fees. Every single product variation, whether it is a change in size, colour, or packaging, must have its own unique EAN barcode physically applied to the packaging before it arrives at the warehouse.

Handling bundles, multipacks and unbarcoded inventory

Selling products in bundles or multipacks introduces additional barcode requirements. A common mistake is assuming that a multipack of three identical items can simply carry the barcode of the individual item. This will cause the warehouse team to scan and ship a single item instead of the multipack, or vice versa.

If you sell a bundle of three bottles of shampoo as a single product, that bundle must be packaged together and carry a new, unique EAN barcode that represents the three-pack. The individual barcodes on the bottles inside the packaging must be covered or obscured so the warehouse scanner does not read them by mistake.

If your products arrive at the warehouse without barcodes, or with incorrect barcodes, they cannot be put away for sale. In this situation, the 3PL will have to perform relabelling services. The warehouse team will print and apply new barcode labels to every individual unit. While this service saves your inventory from being rejected, it comes with an extra cost. Relabelling fees are charged per item and can quickly erode your profit margins. To keep your logistics costs as low as possible, you should always instruct your manufacturer to print the correct GS1 EAN barcodes directly onto your product packaging during production.