Multi-channel operations

Your Barcode 101 Guide: What Do ASIN, UPC, EAN, ISBN, SKU and Other Barcodes Mean?

Your Barcode 101 Guide: What Do ASIN, UPC, EAN, ISBN, SKU and Other Barcodes Mean?

If you are building your retail business on marketplaces like Amazon, eBay, Walmart, Shopify, or others, you won’t do without barcodes. These platforms require you to add product identifiers as you list your goods to manage inventory. But what is ASIN UPC EAN ISBN SKU? Who may need it? Which barcode type will work for you?

Are you haunted by these questions but have no clear answer in your mind so far? Let SellerSkills help you.

Read this quick complete guide to the barcode variety to find out which product identifiers will help you run your eCommerce business more effectively.

What Do ASIN, UPC, EAN, ISBN, SKU and Other Barcodes Mean?

What Is a Barcode?

A barcode is an approach to presenting information about the product as an image or a set of characters.

There are different types of barcodes, we’ll name the most popular ones:

  • 1-dimensional (1D)
  • 2-dimensional (2D)

Every product package has a set of vertical black and white lines with numbers below that are then scanned and interpreted by a barcode scanner. These are 1D barcodes that carry information about what the product is, the country of its origin, and who is the manufacturer. They include numeric-only (UPC and EAN, and others) and alpha-numeric (ASIN, SKU, and more) barcodes that consist of numbers and a combo of letters & numbers correspondingly.

QR codes that use squares, dots, and other shapes to code data are 2D barcodes. These are more complex identifiers that can carry more information about the product, including its image.

This system is highly beneficial for organizations and businesses of all sizes as it allows you to quickly get information about the product using a smartphone or a special device. Barcodes also:


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  • Eliminate the chance of human errors.
  • Allow to process information faster.
  • Simplify tracking and inventory management.
  • Cut costs on employee training.
  • Help run business more effectively.

As you know what a barcode stands for, let’s take a closer look at the most common product barcodes and identifiers such as ASIN UPC EAN ISBN SKU

What Does UPC mean?

What is UPC in simple words? In a nutshell, a UPC barcode (Universal Product Code) is one of the most popular and versatile product identifiers that can be found on the package of almost every product in the USA and Canada. For retail in other countries consider EAN (more information in the next section).

The UPC code consists of two parts:

  1. a series of vertical black lines that is unique to every product and is read by barcode scanners.
  2. a unique 12-digit number below that can be run through a UPC lookup.
UPC Barcode

The UPC number is scanned at checkout or Point of Sale (POS). As it gives information about the product brand, features like size, color, number of units, etc., the code significantly increases the speed of the checkout process. It also comes in handy for managing your inventory within a warehouse or store.

How do I get a UPC code?

If you need a UPC to label your products or you are planning to sell through large marketplaces like Amazon, Walmart, eBay, and others, you must work with GS1, the Global Standard Organization first. You need to apply to become a part of their system to get the Company Prefix number assigned to you by GS1. Then you can use a UPC generator to receive a unique product number and check digit for each product.

What is EAN Number?

EAN barcode stands for the European Article Number. EAN number is a set of 13 numeric characters accompanied by an image-barcode. Just like UPC, it will be displayed on the packing of the item and could be read by a special device, computer, or you can enter the numbers manually if the barcode doesn’t get scanned.

It looks similar to UPC but has some minor dissimilarities which we will cover later. What you should know now is that it is used for the European market to ensure faster product processing at checkout or more effective inventory management. It also helps customers find your items easier and faster, just using the code.

How Do I Get EAN Numbers?

If you are looking for a barcode number, you can buy it from barcode sellers, like Barcodes.pro, or if you already have barcode numbers and want to generate barcode images, then you can use their free barcode generator tool.

Is EAN and UPC the same?

In general, both EAN and UPC are meant to cover the same needs – to standardize the products you would like to trade, to sell your goods through marketplaces, and simplify some critical business processes. But they have some distinct dissimilarities.

Is EAN and UPC the same?

So, if you are doing business in the United States and Canada, you can go with UPC barcodes for your goods. But if you plan to scale your business and go international, EAN will be a smarter solution for you. However, most modern barcode scanning systems are compatible with UPC and EAN and can read information from both.

What Is a SKU?

What does SKU stand for? It’s a Stock Keeping Unit that is described as a unique alphanumeric code the item receives from the retailer to track their stock or sales, making a shopping experience smoother both for the sellers and customers.

Unlike UPC and EAN, the SKU number is not universal, which means that every retailer will have its unique SKU system.

SKU codes are generated to eliminate human inventory errors and to better differentiate between the items in the assortment. Every product feature like supplier, category, brand, model, size, color, and more gets a unique set of letters and numbers. You can even set a store or warehouse location if you have multiple premises.

For example, you would like to sell a T-shirt in three colors (white, black, red) and three sizes (6, 10, 14). Each product parameter will get a unique code set by you.

What is SKU Stock Keeping Units

Some tips for creating an SKU system from SellerSkills:

  • Eliminate the chance of human errors.
  • Allow to process information faster.
  • Simplify tracking and inventory management.
  • Cut costs on employee training.
  • Help run business more effectively.

Is SKU and barcode the same?

SKU is another type of barcode. Some barcodes are universal (like UPC, EAN, ISBN). In other words, they are used by all the sellers of the same product all over the world. They allow better product differentiation on a global scale. Others, like SKUs, are created within the company to ensure more effective stock control, simplify sales, and eliminate errors.

What is ASIN?

Amazon ASIN number stands for Amazon Standard Identification Number that was created by the marketplace to manage its constantly growing market. Amazon defines them as unique blocks of 10 letters and numbers that are used to identify the product on their platform. It is unique for every item you are going to sell on Amazon. The ASINs are valid only within this sales channel and are not working for eBay, Walmart, or other marketplaces.

This ASIN number is useful for both parties, the seller and Amazon itself. The merchant can easily track the inventory and index catalog pages for search, while the marketplace uses the ASIN code to reference the data when the users are looking for similar or the same products.


Use an Amazon ISBN rather than ASIN to identify books or other published materials.

How do I find my Amazon ASIN?

You can find the ASIN number for every product in your Amazon Seller Central account. Or you can go to the product page on Amazon.com and find your product’s ASIN in the Product Information section along with other data.

What is ISBN number?

Just like any product needs a UPC or EAN for its identification, text-based materials (books, magazines, ebooks, and other published stuff) can be marked with ISBN, an International Standard Book Number. The code carries information about the book registrant, title, edition, format, etc.

What is ISBN Number

There are ISBNs with 10 and 13 digits. Those numbers that were registered before the end of December 2006 have 10 digits, while those that are released since 1 January 2007 till now contain 13 digits in length.

Why Is ISBN Important?

Every book version and edition gets its unique ISBN. As books and other publishing materials are frequently published worldwide and in several editions, an ISBN is a great way for publishers to monitor the sales volumes of every book edition.

What is ePID on eBay?

ePID is eBay’s answer to ASINs on Amazon. These are identifiers that are used to list products in their catalog. You can use it instead of UPC. The marketplace requires this identifier to list new items. You can also use it for the item search within the platform.

What is a GTIN?

GTIN is a Global Trade Item Number that is given to a product for identification. The GTIN number could be applied globally and it contains from 8 to 14 digits depending on its form.

There are several forms of GTIN depending on the type of the product and where it is sold:

What is GTIN

So, in fact, these identifiers are the form of GTIN. But regardless of their form, they all stick to the same structure:

  • Country index.
  • Company prefix.
  • Product reference.
  • Check digit.

Is UPC the same as GTIN?

GTIN is the general term that combines common barcodes like UPC, EAN, ISBN, and JAN.

What is GCID?

GCID is the Global Catalog Identifier assigned by Amazon to the brands that have successfully completed Amazon Brand Registry. This number identifies that the products belong to your brand and it’s the only barcode you can use for your Brand Registered listings.

How do I add GCID to Amazon?

When you apply for Amazon Brand Registry, the marketplace will assign the unique GCID to every new SKU you provide. What it means is that you can get GCIDs only for new items.

If you already have a listing with the UPC or EAN number, you can’t change it to GCID on your own. To make modifications, you’ve got to open a ticket “Fix a product page” and let the Amazon catalog team handle this.

What is FNSKU?

FNSKU is an acronym for the Fulfillment Network Stock Keeping Unit. This barcode is generated by Amazon to identify the product that has been sent by the seller to their fulfillment centers. In other words, every unique item that is eligible for FBA and enters Amazon warehouses should be assigned an FNSKU.

How Do You Get FNSKU?

The process is not tricky. First of all, you need to set the product as FBA. Amazon will then generate FNSKUs for every unique item in your list. If you are using SellerSkills app for FBA listing management, you can easily add the barcodes to our system.

Summing up about ASIN UPC EAN ISBN SKU

We’ve just covered the most popular barcode numbers every eCommerce seller might need to sell on popular marketplaces. To make things even clearer, here’s the chart that shows what barcodes you might need for a specific selling channel.


The variety of barcodes might blow your mind as you see the list for the first time. But, in fact, that’s not that hard. Especially, when you are using SellerSkills. We made the process of adding and managing the barcodes through different marketplaces really simple. You just pick the identifier and enter the barcode when creating a new listing.

Some barcodes are marketplace-tailored. It means that you can get them only through a definite platform like Amazon’s ASIN, FNSKU, and more. Universal barcodes like UPC and EAN can be purchased at Barcodes Pro. They are transparent at their pricing and charge only once, without any additional monthly or annual fees. The company also offers a FREE barcode generator that allows you to get a machine-readable image for your existing UPC or EAN. The free QR code maker is in the work now and it will be released in the shortest time.

Now we hope you know what are ASIN, UPC, EAN, ISBN, SKU.


Run your multichannel biz with ease. Be smart. Be efficient. Be SellerSkills.

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