Google Shopping

What Is a GTIN and Why Do You Need One?

0 · by Dennis Moons · Updated on 27 March 2023

We’re all familiar with barcodes because they are used to identify products at the checkout registry in supermarkets. What most of us don’t know is that those barcodes are actually a visual representation of unique product numbers which convey a lot of information about the item we buy (including details about its manufacturer).

Turns out, these numbers, also known as product identifiers, are very important for ecommerce.

In this piece, we’ll lay out the reasons why online stores need the internationally adopted standard identifier called GTIN.

If you want to learn more about this type of identifier, read on to get the GTIN basics; what it is, its international formats, how shopping platforms (like Google, Amazon, and eBay) use it, where and how to obtain a GTIN for your products, and the benefits of doing so.

What Is a GTIN?

A Global Trade Item Number, more commonly referred to as a GTIN, is a sequence of numbers used to identify products. Each product (trade item) has a unique ID, so what social security number is for people, GTIN is for products.

The GTIN product identifier was established in the 1970s by an international not-for-profit organization called SG1, which put together technical recommendations for the correlation of product data found in different databases. 

The system is adopted on an international level and is a standardized way to note the product manufacturer and the product reference, making it different from product serial number or Stock Keeping Unit (SKU), which are usually used for internal purposes.

As a product identifier, GTIN is integrated with other international standard identifiers. Or, to put it more correctly, other standards, such as ISBN (for books), EAN (for products), UPC (also for products), ISMN (for music), and others, are incorporated into GTIN.

Adherence to rules for providing product identifier data in the GTIN format is voluntary (i.e. not regulated by law). That being said, large online shopping platforms, like Google and Amazon, recommend using GTIN numbers as an identifier for items sold in their stores, and the use of invalid GTINs is penalized .

GTIN Formats

There are four different types of GTIN formats based on the number of digits. 

GTINs can have 8, 12, 13, or 14 digits, and each of these formats is related to the country in which a product is handled or the type of industry. This will become much clearer as we check specific formats:

  • GTIN-8 (EAN/UCC-8) consists of 8 digits and is mostly used in Europe (for EAN barcodes);
  • GTIN-12 (UPC-A) has 12 digits and is used in North America, almost the same as UPC for a product;
  • GTIN-13 (EAN/UCC-13) has 13 digits and is used in Europe, Japan, and everywhere else except North America. The ISBN code for books is also in this format;
  • GTIN-14 (EAN/UCC-14 or ITF-14) has 14 digits and is used for products coming in bundles as wholesale items or in packs (to designate packaging level).

Detailed GTIN Structure

These 8-14 digits are organized in a specific data structure to convey info about the product. The digits serve as one of the following four components:

Indicator digit

It has a value from 1-9 and indicates packaging level, so it’s only used for GTIN 14 (position 1);

Company prefix

It’s a globally unique company number (registered with GS1) and can be of a varying length (positions 2 through 13);

Item reference

It’s a product number assigned by the manufacturer and provided to GS1 to identify the product (positions 2 through 13);

Check digit

It’s the last digit, used to ensure that the rest of the GTIN was put together according to specification rules (position 14).

If a GTIN-8 is represented in a GTIN-14 format, zeros are added to the left of the first digit in the GTIN-8 number. These zeros have no value, and are added as a placeholder. For example, to express the packaging level of a product identified with GTIN-8 number, positions 2 through 6 will be all zeroes.

How are GTINs Used?

GTINs can be represented in machine-readable code using parallel lines of varying width, like a barcode. So think of all the possible applications of barcodes and the same applies to GTINs.

Primarily, manufacturers use GTINs to assign a unique identifier to each product in their inventory. This helps improve tracking the changes in the product catalog both within the company and in other stages of supply chain operations, given that it works much better than using product names. 

For example, if the manufacturer labels the product as “Pocket Knife XS,” the supplier labels it as “Leatherman Pocket Knife”, and the retailer labels it as “Every Day Carry Pocket Knife XS”, this will make product tracking more complex than it has to be.

In a nutshell, GTIN it’s the fastest way to share data on individual product items and eliminates the possibility of mistaking one product for another because both you and the other party (your partner or customer) are using the same reference for each item.

Use of GTINs in Ecommerce Data Feeds

Shopping platforms take this application of barcodes (or GTINs) to another level. Having a unique and specific identifier for the products in your ecommerce shop helps:

  • Serve a product ad that’s a more relevant match for the user’s search query
  • Compare products available on the platform (or on multiple platforms, if the search query is entered in a shopping comparison engine)
  • Provide an ad creative with a photo of the exact product

Let’s check how this works on some of the most popular ecommerce platforms: Google Shopping, Amazon, and Ebay.

Google Shopping

We all know that Google considers its inner workings to be a trade secret and keeps them from the public. However, when Google started using GTINs for branded products with product condition “new”, they also shared a reported increase of clicks by 40% for merchants who use GTINs as a product attribute in their feed. 

This shows us that products with GTINs have a better chance of getting matched in Google Shopping and the users find the ad results to be relevant.

How does this work?

What Does Google Learn From the GTIN

From a practical point of view, GTIN helps Google to establish basic facts about the product. Things like the correct brand (or whether merchants provide an inaccurate or misleading product title), detailed specification and packaging level (for products that come in a bundle or a case), etc.

It all boils down to positively identifying the unique and exact product reference so that the end result of processing the data is more relevant.

Is GTIN Used To Define Google Ads Audiences?

Google algorithms are unknown, but it’s suspected that GTIN also plays a role in correlating product-related searches with user data.

Suppose you analyze the online behavior of users who engaged with a specific product – you might start noting patterns. For instance, users who entered a search query xyz about the product x also share q and w in their search history. This might be useful for creating Affinity or In-market audiences.

What we do know about GTINs and Google is that having a unique product identifier is better for your Smart Shopping campaigns. How?

Advertisers usually change product titles and product descriptions as part of their product feed optimization efforts. If you don’t have a GTIN, Google will be confused when you change the title of the product (possibly identify it as a new one) and all of the performance data up to that point will be scraped.

When your product has a GTIN, feed optimization won’t affect audience data in a Smart Shopping campaign, because the product is positively identified through a numerical code.

GTIN Tips for Google Shopping

Google sometimes blocks (either partially or totally) products that don’t have GTINs from accessing Google Shopping features. That’s why GTINs are so important to ecommerce merchants – correct GTINs for each of your products indirectly affects the success of your campaign.

This is especially important for online stores that are reselling other brands, because GTINs allow them to stand out and get better visibility. On the other hand, stores that sell their own products will not experience significant change in performance if they do business without a GTIN. 

Entering a random string of numbers instead of the correct GTIN is not a workaround that will solve the product feed issue. In fact, merchants are encouraged to provide an additional unique product identifier, like Manufacturer Part Number (MPN), to legitimize both themselves and the product.

We’ll provide more info on solving the “incorrect GTIN” issue further below.


Amazon is a marketplace, and GTINs help to improve the quality of the overall product catalog and product selection options when buyers compare different offers. This is why sellers are required to provide unique product identifiers for each item. 

Sometimes, these identifiers are referred to as UPC or Universal Product Code, however, this is the same as GTIN-12.

Many Amazon sellers used to get their GTINs from 3rd party reseller companies and not directly from GS1. This is no longer allowed (products need to have the right GS1 Company Prefix), because GTINs acquired from resellers usually have Company Prefix that’s already used by other sellers (more on this below).

By banning GTINs from 3rd party resellers, Amazon can easily solve disputes about counterfeit products and determine which of the two (or more) sellers actually sells original products.


eBay is another popular marketplace where search engines need to provide a match between buyers and items (within the platform and from its own internal product catalog). They use the same standard for product identifiers – it can be a GTIN or MPN.

This applies to branded products that are new or refurbished by the manufacturer. The benefits of using unique product identifiers, like GTINs, on eBay, are a boost in visibility and improved product listing information (comprehensive item specifics and accurate pricing tips).

Most ecommerce platforms have guidelines for using GTINs that are similar to those for Google, Amazon, and eBay. So, in a way, if you get a GTIN, you solve the problem on a product feed level and then it’s easier to maintain your presence on multiple platforms.

Let’s check the procedure for getting a GTIN.

How To Find the GTIN of Your Product?

When an advertiser gets a notification about a feed error “missing GTIN”, the best way to resolve the issue is to provide the correct GTIN. But how do you find it?

The simplest way is to check the product’s packaging – identifiers are usually included below the barcode. Of course, you need to have the physical product on hand to do this.

If you don’t have the product in front of you, or if there is a long list of products in your inventory, you can use faster methods. Contact your supplier or the original manufacturer – they should have this data, even for a large number of entries in your product catalog.

Alternatively, you can find the GTIN number online.

Sometimes, you are both the manufacturer and the advertiser. Let’s check what to do in that case.

How Do You Get a GTIN?

If you don’t have a GTIN for your product, you have to buy one from GS1. They cost around 30 USD per number, but this can vary (the price will be lower if you buy GTINs in bulk, i.e. for multiple products).

There are two types of GTINs: individual (for those who need to register a small number of products) and licensed (for a whole line of products, and this is what most companies use).

The license, also known as GS1 Company Prefix, is a prerequisite for getting a lot of GTINs at once, and the procedure for registering it is very easy. You need to provide basic info, like company name, contact details, number of products, and payment details, and that’s it.

Structure of Your GTIN

If you have a GS1 Company Prefix, the structure of your GTIN will be as follows:

Your GS1 company prefix number

The first three digits are a country code (the country in which your company is registered, not where manufacturing takes place). The GS1 Company prefix will be the same for all of your items.

Item reference

You can follow your own logic for assigning an item reference number as long as it’s unique for each item.

Check digit

Also known as checksum, is calculated using GTIN numbers in positions 1 through 13 to ensure all the other digits are correct.

GTINs Company Prefix has an expiration date (they are valid for a year), and once this period is over, you need to pay an annual renewal fee. If you don’t, GS1 will remove your company listing from their database (GEPIR) and cut your access to their Data Hub tool. This rule applies even if you don’t add new item numbers (i.e. you need to pay to continue using the company prefix for products registered earlier).

One GTIN per Item

Don’t forget that the whole point of having a GTIN is to assign one globally unique identifier to each item. Getting a GTIN costs money, and some merchants are tempted to cut some of those costs by registering one GTIN for a bundle of products.

Usually, this is done by bundling up different sizes and colors of the same product in one GTIN.

For example, if you sell a wingtip dress shoe, all of your wingtip shoes are referred to by the same GTIN, regardless of color (black, brown, burgundy, tan, etc.) or size (5.5-16.5 in the US, or 39-50 in Europe).

This will solve your product feed issue “invalid GTIN” in Google Merchant center, however, it hinders optimal campaign performance. Conversions will be misattributed and this will affect many metrics along the way. Following on the example from above, this means that Google will not be able to determine whether your black wingtip outperforms your brown wingtip.

Selling Products Without a GTIN

Is there a category of products for which it’s recommended not to use GTINs? Even though it’s not advised to sell items without a GTIN, Google Merchant Center has a functionality that allows you to specify that there is no GTIN for your products.

In fact, many online merchants sell products without a GTIN (it’s a common practice) and there are a number of ways to avoid providing identifiers.

Let’s check some of them out.

How To Avoid the Use of GTINs for Products in Your Store

When you get a notification that products in your feed are affected by the issue labeled as “Incorrect value [identifier exists]”, one possible solution is to inform Merchant Center that GTIN doesn’t exist for those products and you can’t provide it.

Usually, this applies to art pieces, antiques (vintage products), and handcrafted or otherwise custom-made objects, like jewelry. Used items (resold items) and collectibles can also be sold without a GTIN. To specify this as a product attribute in the feed, set the product identifier value (identifier_exists) to NO (i.e. False).

On Amazon, this option is known as GTIN exemption, and most online marketplaces have a version of it for these types of products (vintage, custom, etc.). On eBay, you can select “does not apply” in the field for providing GTINs.

However, there are reasons retailers should do their best to get unique product identifiers. Let’s check them out.

Advantages of Having a GTIN

We already discussed the role of GTINs in improving product catalog quality and providing relevant matches on platforms like Google Shopping, Amazon, and eBay. In this section, we will cover the benefits of GTINs from the perspective of sellers and customers.

Advantages of GTIN for Retailers

Sellers invest in buying GTINs for each of their products because this pays off in the long run. Here are some of the ways retailers benefit from GTINs:

They enable you to sell on multiple platforms

Unique product identifiers are an industry wide standard and although some platforms may have specific requirements, like Google requesting MPNs, all identifiers boil down to GTINs. Once you do this on one platform, it’s easier to set up shop on another.

They help improve sales

GTINs make it easier to match the right product with its potential buyer; product ads and search results are more relevant, and this translates into a boost in conversions.

They are a way to optimize your campaigns

Platforms favor retailers who comply with their rules. For example, products with GTINs are more likely to feature a “Trending price alert” on eBay for products with lower price AND a product identifier. It’s a sort of incentive, and every platform has a version of it to reward those retailers who did what was requested of them.

There are also advantages that aren’t directly related to ecommerce, like making your business processes more efficient. With GTINs, it’s easier to handle SKUs from your inventory all across your distribution network. This results in improved performance of your business overall.

Now, let’s take the customer’s perspective.

Do Customers Use GTINs?

Although the concept of globally unique identifiers for products was introduced to make life easier for manufacturers, suppliers, and retailers, customers can also use GTINs to find better offers.

It’s rare and done only by a small number of users, but those who do it know exactly what they are looking for.

The fact they’ve entered a GTIN number in a search engine to find a product indicates high purchase intent and targeting this group of users is very valuable for retailers.

Some of the reasons customers do product-based searches include:

Making comprehensive product comparison

They are not checking what individual sellers have to offer but rather where the right product can be found. It’s a shift in perspective, and they are likely to find a better offer in terms of price or quality and get the exact item they are looking for.

Getting relevant products as shopping search results

It works as a filter for shopping search results: entering a GTIN as a search query automatically eliminates results that have nothing to do with the product you want (i.e. you filter out similar, upgraded, replacement, or alternative products).

Getting relevant suggestions on many other platforms

As different ad campaigns, like Google Display, follow these users around, they’ll get more relevant ads based on their GTIN searches. It’s kind of a shortcut to finding out what a customer really wants.

Product Data in Google Manufacturer Center and GTINs

Retailers are well versed in Google Merchant Center because they use it as an interface for providing product data. However, they don’t have all the product data since the items they sell were produced by someone else.

Google has a similar interface for manufacturers, known as Manufacturer Center, where the company that makes the product can directly upload product data. Logically, this info is usually more comprehensive.

Manufacturers can provide descriptions, images, titles, or videos of the product. This improves Google’s catalog with detailed product data. GTINs provided by retailers on a shopping platform identify the product and if that product is registered in Google Manufacturer Center, shoppers will get a better match.

Alternative Product Identifiers

As we mentioned earlier, GTIN incorporates other formats for product item numbers that are unique on a global level. Platforms may prefer to label the product identifier in a certain way, so it’s useful to at least know what these different acronyms mean.

Also, some of the product identifiers listed below are separate from GTIN, but are often used alongside GTIN, so do note them as well.

Let’s check out these alternative product identifiers:


It stands for Manufacturer Parts Number. It’s assigned by the manufacturer and is different from GTIN. MPN serves to verify that the product is original and not an unauthorized copy or counterfeit. In Google Merchant Center, MPN serves as an additional product identifier (other than GTIN).

The format of MPNs is not standardized (it’s up to the manufacturer). The only rule about its structure is to be alphanumeric, but it can be numbers only or letters only as well.


It stands for Universal Product Code. It’s virtually the same as GTIN-12. By SG1’s definition, UPC usage is to facilitate scanning products at the point of sale (i.e. the reason barcodes are engraved on packaging).

The format of UPC is:

  • number system character – denotes the type of product (position 1); for example, drugs start with “3”
  • manufacturer code – GS1 Company Prefix (positions 2 through 6)
  • product code – assigned by manufacturer (positions 6 through 11)
  • check – 1 checksum digit to check if the other numbers are correct (position 12)


The International Standard Book Number. It has the same format as GTIN-13 and it’s used for identifying books and similar publications, mainly on Amazon (but also many other platforms). Same as with any other product item, each new edition of the same book needs to have a new ISBN number. So, if someone wants to purchase the “revised” edition of a book, there will be a unique reference to it.

ISBNs structure is as follows:

  • GS1 prefix – 978 or 979 (positions 1 through 3)
  • registration group – 2 digits that specify language or country (positions 4 and 5)
  • registrant – i.e. the publisher, 4 digits (positions 6, 7, 8 and 9)
  • publication – book reference or title, 3 digits (positions 10, 11 and 12)
  • check – checksum, 1 digit (position 13)


Stands for European Article Number. It’s also referred to as the International Article Number or IAN. It’s used for checking barcodes in retail, but it can also be used in logistics, or accounting.

There is a shortened 8 digit format of EAN (for small packages), however, the most common is the EAN-13. Its structure is:

  • GS1 prefix – 3 digits that specify country or type of product (positions 1 through 3)
  • manufacturer code – GS1 Company Prefix (positions 3 through 12)
  • product code – assigned by manufacturer (positions 3 through 12)
  • check – 1 digit (position 13)


Stands for Japanese Article Number. It’s almost the same as EAN, the only difference being a prefix 45 or 49 at the start.

Align Your Products With the Language of Shopping Engines

There’s a reason IT professionals prefer digits to letters (and other symbols) – it eliminates the possibilities for misunderstanding. Standardized numerical product identifiers are in tune with the language of search engines (be it for shopping, price comparison, or other uses).

GTINs are adopted on a global level, and by getting one for each of your products, you not only solve a product feed issue, but you also reap many other benefits: 

  • Your products will be matched with relevant shopping queries; 
  • You will get better performance monitoring for Smart Shopping campaigns;
  • Counterfeit products can be easily identified because you helped improve the product catalog on the shopping platforms;
  • Product data provided by manufacturers can be pulled for your dynamic product ads;

and many others. 

In a nutshell, shopping engines will reward you for playing by the rules.

Dennis Moons

Dennis Moons is the founder and lead instructor at Store Growers.

He's a Google Ads expert with over 12 years of experience in running Google Ads campaigns.

During this time he has managed more than $5 million in ad spend and worked with clients ranging from small businesses to global brands. His goal is to provide advice that allows you to compete effectively in Google Ads.

Follow him on Twitter or LinkedIn.


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