A single product can have many associated codes.

If you’re a retailer, which of the many product codes should you be using? UPC, ISBN, ASIN, EAN- there are several to pick from.

How do you map these codes back to the products and ship the right one? Most importantly, why do we need codes, and can we sell without them?



Indeed, until the time when stores used manual billing only, having product codes was not a prerequisite for selling. It was redundant even, to take a product that both the retailer and customer can recognize and then proceed to attach a code to it.

However, with the advent of mass manufacture and several stores selling the same product, we need codes, much like names, to identify each product.

Codes, or product names, are a way to uniquely identify your products and this is often considered to be an inventory management best-practice. Before you get into the codes, it is worth spending some time to understand inventory management better and see how you can do business better with it.

What is ISBN – International Standard Book Number

Just as products are uniquely identified by UPCs, books, magazines, e-books and other published media can be uniquely marked using ISBN. Every book that goes into publishing must have an ISBN code attached to it. (Edit: A reader has just brought to our attention the fact that self-published books need not mandatorily have an ISBN, although it is definitely recommended. Thank you, Mike!)

What’s more, different editions of the same book will have different ISBNs. For example, Harry Potter and the Philosopher’s Stone has the ISBN 0-7475-3269-9 while its illustrated edition has the ISBN 0-5457-9035-2.

Why is an ISBN so important? Books and published media often travel and sell all around the world, hence the ISBN is a good way for a publisher to keep track of how much it is selling and where.

As opposed to using the name- the first book in the Harry Potter series sells by the title of ‘Sorcerer’s Stone’ in the United States and ‘Philosopher’s Stone’ in the UK and some other countries – using an ISBN is a better way of identification and tracking.

How do you register an ISBN?

Each country has a national ISBN agency. Depending on where you live, you need to approach the agency with information about the book and author.

If you’re publishing your own work, it is possible to apply for a single ISBN and cut costs. Here’s a detailed look at the procedure.


What is UPC – Universal Product Code

As the name implies, this coding is universal, in that every retailer and every marketplace would use the same code for a certain product. This is the code that goes into barcodes and helps stores keep track of sales. This is the code that helps a manufacturer identify how much of a product he has sold worldwide.

Related: What type of barcode scanner should I use?

A UPC is typically 12 digits long and represents attributes such as the weight of the product, the product type, name, etc.

Why are these attributes important? Because a machine (barcode reader) ‘reads’ this code and links its attributes to a certain price. Indeed, the advent of UPC has made possible the use of computerized billing and faster checkouts.


A UPC applies to virtually every category of products you can think of, from electronics and clothing to food, medication and even services.

In order to get a UPC for your products, you first need to register with GS1 and obtain a company code. You prefix this code to all your products to help identify you as the seller.

Once you have this code, you have to assign unique numbers to each of your products. You can then order as many barcodes as you like. Here’s a link to where you can do it.




What is EAN – European Article Number

For a long time, we assumed that products manufactured within US and Canada would sell in these territories alone. We also thought that manufacturers would produce these goods locally as well.


Common knowledge and time have shown that this is often not the case, hence the need for an EAN. The EAN is the same as a UPC, except it has a single digit country code prefixed to it, thus making it 13 digits long.

If your customer base resides in the US and Canada, stick to a UPC as most older barcode readers can only recognize the 12 digit UPC. If you’re selling internationally, you’ll need an EAN.

What is ASIN – Amazon Standard Identification Number

With marketplaces as huge and geographically diverse as Amazon, it makes sense for them to have a unique identification code for the products they’re selling. As a retailer, you can

  • attach your product to an existing ASIN (of the same product from a different seller), or
  • register your brand on Amazon and get new ASINs assigned.

This helps both you and the marketplace keep track of inventory. It also prevents them from accepting orders for products that have run out.

The catch here is that unlike a UPC, an ASIN is not necessarily unique to a product. Say you’re selling the same product on Amazon US and Amazon UK. Your product could have different ASINs on these sites.

The only time when an ASIN is universal is when it is matched to a book’s ISBN. Consequently, if you’re selling books, you don’t need to worry about ASIN being a different number. It is almost always the same as the book’s ISBN.

What is the significance of ASIN to you?

When you manage inventory and ship products, you’ll find that orders from Amazon will be marked with their ASIN.

So the request you get has an ASIN on it that you need to further map to the right product from your inventory. Only then can you ship the correct product.

Jewelry, beauty products, and personal care can be sold on Amazon without a UPC. Once you upload them, an ASIN is assigned to them.

Related: What type of barcode scanner should I use?

Coding each product may seem like a hassle. Consider how many miles each product travels before it gets to the customer. Several people will be handling it in the meantime.

The packaging department, shipping, and last-mile partners are involved. Without a unique code to identify products, you may just end up shipping the wrong product. You put it through this entire process for no good reason.


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