For all businesses, both large and small, one of the first steps to trading, both online and offline, is to assign unique identification numbers to your products in the form of a Global Trade Item Number (or GTIN for short). GTINs allow you to unlock all relevant product information to your items, allowing you to successfully list and sell your product, barcode your stock, leverage search engines, manage inventory and even monitor customer satisfaction.

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This small but powerful number is a sure-fire way to ensure a seamless sales transaction for any product.


  • To start assigning GS1 numbers and barcodes to your products, as a UK seller, you need to:

  • Become a member of GS1 UK, which can be done easily online via the GS1 UK website

  • Log in to the member portal, My GS1, to access and manage all your GS1 numbers

Start assigning GS1 GTINs to your products You can find out more here:


GTINs are unique - GTINs uniquely identify a product by combining three things:

  • The country where your number was licenced

  • Your company name used to join GS1

  • The product itself

-GTINs are valid for all the major marketplaces and retail stores

-GTINs are traceable across the supply chain

-GTINs are universal - your GTIN can be scanned and recognised anywhere in the world

-GTINs are authentic - GS1 is the only official source for GTINs and guarantees that your numbers are licenced to your brand

For more information check out GS1 UK’s ultimate guide to GTINs 


All products must be assigned a unique GTIN before trading. This enables your trading partners to track your product more accurately through the supply chain and ensures consumers are receiving the product they purchased.

The first step is deciding how many GTINs you require for your product range. For example, if you have a t-shirt in three sizes you would need three unique GTINs. If you have three sizes and three colours you would need nine unique GTINs. And if you had three sizes, three colours, three styles and three packages, you would need 81 unique GTINs. 


Sometimes you will need to make a change to a product, which can mean you need to assign it a new GTIN. This is because changes in the packaging material can affect the gross weight of an item and therefore, may impact the logistics processes involved in the product’s handling.

Similarly, if your product has changed materials, which effectively creates an entirely new product, this then needs to be noted in the GTIN number. Otherwise, you may find yourself with a few unhappy customers wondering why they didn’t receive the product they thought they had ordered… or worse.

To help you to understand when you need a new GTIN,

follow the three guiding principles:

  • Is there a consumer impact?

  • Is there a consumer impact?

  • Is there a significant supply chain impact?

If you answered yes to one or more of the above, then a new GTIN is required. To double-check if you need a new GTIN, use GS1 UKs decision tool: 


When producing product packaging you need to ensure your barcodes are readable by a scanner, are correctly encoded and printed within the allowable range of sizes, to be read correctly on the first scan.

To ensure your barcode is correct before including it on the packaging of your products, you must:

Choose the correct barcode: EAN-13 are the most commonly used barcode and is used for items to be scanned at retail Point-of-Sale (POS)

  • If your product is a similar shape, put your barcode in the same place

  • Ensure the barcode image is on a flat or the flattest possible surface, and avoid labelling around corners

  • The barcodes on consumer units must not be visible through the outer case packaging

  • For small cylindrical products, the barcode must be positioned vertically so that the curvature of the product results in an apparent loss of height of the bars

  • Print barcode images so that the darker bars are against a lighter background

  • Avoid red or “reddish” colours for the bars - the red-light scanners will not pick them up

  • Printing size: ensure you have the correct minimum printing size (magnification) and bar width reduction

  • (BWR) for a usable end-product

  • Verify your barcode to make sure it works correctly

In partnership with Great British Entrepreneurs, GS1 UK are pleased to offer new members a 20% discount on their first year’s membership.  Please click here and use discount code GBEA20 at the checkout.