What are product identifiers and GTINs? Their benefits and where to find them

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Product identifiers are a series of numerical or alphanumerical digits that are used to identify a specific product. Ultimately, they are the key to helping customers locate products online, and commonly include Global Trade Item Numbers (GTINs), Manufacturer Part Numbers (MPNs) and brand names.    

With the likes of Google, eBay and Amazon now requiring sellers to provide unique product identifiers for each product they sell, it is integral that you are familiar with the different types of product identifiers, and how you can obtain them.

The different types of product identifiers

Brand name

The brand of a product.

Format – Name of Brand.

Manufacturer Part Number (MPN)

A Manufacturer Part Number refers to the number which uniquely identifies the product to its manufacturer.

Format – Alphanumeric digits of various lengths.

Global Trade Item Number (GTIN)

A GTIN is a unique identifier for trade items, products of services. GTINs are assigned to most retail products in and include UPCs, EANs, JANs and ISBNs.

Format – GTINs may be 8, 12, 13 or 14 digits long.


A unique numerical identifier for smaller items that cannot fit a 12 or 13 digit barcode image on the packaging.

Format – 8 numerical digits.

GTIN-12, also referred to as Universal Product Codes (UPC)

A unique numerical identifier for commercial products that is usually associated with a barcode printed on retail merchandise. UPCs are primarily used in North America. Format – 12 numerical digits.

GTIN-13, also referred to as European Article Number (EAN)

A unique numerical identifier for commercial products that is usually associated with a barcode printed on retail merchandise. EANs are primarily used outside of North America.


A unique numerical identifier for cases of commercial products. Please note – what is referred to as a GTIN, within Amazon Seller Central it is actually a GTIN-15, and sellers should select EAN as their identifier.

Format – 14 numerical digits.

Japanese Article Number (JAN)

A unique numerical identifier for commercial products that is usually associated with a barcode printed on retail merchandise. JANs are used only in Japan.

Format – 13 numerical digits.

International Standard Book Number (ISBN)

A numerical identifier for commercial books published since 1970. This can be found on the back of the book, along with the barcode.

Format – ISBN-10:10 numerical digits (last digit may be “X” which represents the number “10”). Note that this format was deprecated in 2007 and not all books can be represented using ISBN-10. ISBN-13 (recommended):13 numerical digits, typically starting with either 978 or 979.

Further reading: How To Calculate Inventory Turnover: Formulas & Examples

Benefits of using unique product identifiers

While there are a number of benefits to using unique product identifiers, each of which covered below, perhaps the key thing to bear in mind is that as a seller you are required to provide this information for each product listing, when selling on eBay, Amazon and Google.

In addition to this, the use of product identifiers further helps you increase listing visibility, rank higher on search engines and cross-promote your listings next to relevant products.

Another important reason for using these product identifiers, not only on marketplaces where they are required, but also on your own website, is because of the increasing importance of search.

In fact, online advertisers who follow Google’s GTIN requirements will see a 40% increase in click-through rate, as well as a 20% increase in conversions.

The fact is, advancements in technology is making SEO increasingly complex, with search engines now focusing on the searcher’s intent, as opposed to the exact words or phrases used.

The challenge, however, is that machines cannot read and interpret information the same way a person can, which is why barcodes help search engines, marketplaces (e.g. eBay) and websites provide the most relevant product when returning search results.

Where to find product identifiers

The unique product identifier can be easily found on any individual product.

Specifically, Global Trade Item Numbers, Universal Product Codes and European Article Numbers can be found below the barcode on retail merchandise.

International Standard Book Numbers can be found both directly above the barcode, as well as in the first couple of pages of a book.

You can also use the Barcode Lookup tool to quickly find out what type of GTIN any given item is categorized as.

If you are selling your own branded products, you will need to purchase a GTIN from GS1, and if you aren’t the owner of the brand, you may need to get in touch with your supplier.


How do product identifiers impact the online shopping experience for customers beyond just helping them locate products?

Product identifiers go beyond merely aiding customers in finding products online. They contribute to increased listing visibility, higher search engine rankings, and facilitate cross-promotion of listings alongside relevant products. Additionally, adherence to Google’s GTIN requirements can lead to a 40% boost in click-through rates and a 20% increase in conversions for online advertisers.

Are there any specific regulations or standards regarding the use of product identifiers, especially in different regions or industries?

he use of product identifiers is often mandated by online marketplaces like eBay, Amazon, and Google. However, there may also be industry-specific regulations or standards governing their usage. These regulations can vary across regions and industries, so it’s essential for sellers to familiarize themselves with any applicable rules.

What are the potential challenges or limitations associated with obtaining and using product identifiers, particularly for sellers who are not the owners of the brand?

Obtaining and using product identifiers can pose challenges, particularly for sellers who do not own the brand. For instance, you may need to purchase GTINs from organizations like GS1 if you are selling your own branded products. Alternatively, if you are not the brand owner, you may need to coordinate with suppliers to obtain the necessary identifiers, which can add complexity to the process.