At some point, every indie author comes up against the question—do I really need an ISBN? Finding a definitive answer to that is going to be tough, thanks to a plethora of opinions from both professional and hobbyist publishers. Those opinions range from “you must” to “you should never,” and every possible answer in between. In this week’s post we’re taking a hard look at ISBNs, digging around a little, and offering our own advice about when or if you should purchase an ISBN. Our answer may surprise you.

Special thanks to D2D’s impressively brilliant Customer Service Manager, Tara Robinett, and our incomparably kind Operations Manager, Steed Brown, for contributing huge chunks of the post you’re about to read.

What is an ISBN, anyway?

We tend to take ISBNs for granted as just being part of the whole ecosystem of publishing, but just in case you’ve wondered, here’s the skinny:

ISBN is an acronym that translates to International Standard Book Number. It’s a 10 or 13-digit code that helps with keeping track of your book, mostly as part of a larger inventory system.

You might also know them by their street name, “Barcode.”

Since 1970 most books have had unique 10-digit ISBN, and in 2007 the 13-digit ISBN was introduced. For some reason.

Here in the US, ISBNs are issued by Bowker—the official agency responsible for issuing identifiers for print and digital books. As an author or publisher, you can buy ISBNs on an individual basis, or buy them in bulk. Or, funny enough, you can opt not to buy them at all.

In fact, many indie authors go without an ISBN, opting to save that money for use on other things, such as editing, cover design, and promotion.

Whether or not that’s a good idea has been the topic of a great deal of debate—and the issue likely won’t be solved in this post. It’s a choice every indie author is empowered to make, however, so we’ll take a look at some of the pros and cons. First, let’s answer another pressing question.

What’s the purpose of an ISBN?

That one’s simple: Complete, accurate identification.

An ISBN is used to identify one specific version of your book, and there should be a unique ISBN for every iteration of your book.

For example, your hardbound edition would have one ISBN while your paperback edition would have another. Likewise, your digital eBook edition would also require a unique ISBN—but here’s where things get a little hazy.

That’s an important fact to keep in mind, and so it bears repeating: You must use a different and unique ISBN for every version of your book. You cannot use the same ISBN for paperback as you used for hardbound, and you cannot use the ISBN from either your paperback or hardbound book as the identifier for your eBook.

New book version, new ISBN.

One issue we see often is an author using their CreateSpace print ISBN in the digital ISBN field on our publishing page. This won’t work, and it can cause issues with the vendors.

Bowker has rules that state you should register a separate ISBN for each digital version of your book—meaning your ePub, PDF, and MOBI files should each have their own ISBN. However, most authors generate only an ePub of their work, because all vendors accept ePub as a source document. Some vendors, such as Amazon, will convert the ePub to a different format (MOBI, for Amazon) after the fact, but the original source file can start as an ePub. Which means that if you got an ISBN for your ePub, and then uploaded that to various vendors who then converted it to something else, you’re really only distributing one version of your book. So you wouldn’t need additional ISBNs.

See how tricky that can get?

There’s no need for a new ISBN for each digital version of your book, because these are just different file formats containing identical information—an ebook is an ebook is an ebook.

Obviously Bowker would prefer that you buy a new ISBN for each digital edition. Understandable, considering they make a profit from each ISBN sold in the US. But the definition of what constitutes a separate edition, everything spun from your single ePub file is considered the same book.

For more information about Bowker’s terms and rules visit

Vendor-provided ISBNs

Even though you can purchase your own ISBN at any time, a lot of vendors can provide you with a free ISBN as part of publishing through their service.

Most larger vendors, in fact, would prefer that you use their internal, stock ISBNs for tracking purposes, as those numbers are easier to document within their own systems. In fact, some vendors won’t display a user-provided ISBN at all, and instead use an internal numbering system, equivalent to an ISBN but unique to that vendor.

Here are some examples of vendor-equivalent identification numbers:

  • When you upload a file to KDP, Amazon will assign your book an ASIN—the Amazon Standard Identification Number. This is a unique 10-character alphanumeric code that Amazon uses for its internal inventory system, and it’s functionally equivalent to an ISBN.
  • Barnes & Noble will assign your book an European Article Number (EAN)—a unique 12- or 13-digit identification number that helps with inventory tracking.
  • Apple prefers to use their own internal Apple ID Numbers, and will not display the ISBN even if you provide one.

In each of the three examples above, the retailer provides their unique identifier for free, and your book gets one regardless of whether you’ve purchased an ISBN or not. From this you can see that purchasing an ISBN for your book may not bring you much benefit, at least with those three vendors.

How about an ISBN from D2D?

Since we’re here …

Draft2Digital offers free ISBNs when uploading through our site, but note that our ISBNs can only be used through our service, and cannot be reused or transferred to a vendor we do not support. For example, if you upload your book to D2D and opt for one of our free ISBNs, that identifier will be associated with your book for every vendor you distribute to through us. Once you take that book elsewhere, however (such as uploading your D2D-generated ePub or MOBI file to Amazon or some other Vendor), your ISBN won’t be going with you. You’ll get a vendor-assigned identifier, and if you want an ISBN you’ll have to register one unique to that version of the book.

The reason for this is a regulation that comes directly from Bowker—the agency assigning ISBNs, and who makes the rules. D2D is bound by their terms of use, and by extension so are our authors.

Likewise, if a user has previously been assigned a free ISBN from a different aggregator or publisher (such as Smashwords or CreateSpace) they cannot use that ISBN when publishing their book through Draft2Digital. Again this is part of Bowker’s rules and regulations on ISBN usage, and it adds to the confusion and frustration surrounding the very nature of an ISBN. For more information about D2D-Provided ISBNs, check our FAQ or reach out to our support team at

Just the cost of doing business?

Despite all the shuffling and shenanigans associated with getting an ISBN and transferring it across vendors, many authors and publishers still hold firm to the idea that an ISBN is a necessary part of being in the business. They reason that it helps retailers to easily identify and order books, helps to keep inventories straight (and vendors happy), and even helps legitimize indie books to a degree.

With those considerations in mind, buying an ISBN can seem like just part of doing business. However, unlike a well-designed cover or professional editing, having an ISBN won’t typically make or break a book. In fact, it’s generally a non-event for most authors, and can even be a pointless expense for new authors.

“My personal take is fairly straightforward,” says Kris Austin, D2D’s CEO. “No new author should worry about or care about ISBNs. There is no advantage to having one when you’re starting out, and the expense will get you.”

Which isn’t to say that ISBNs never have their place.

“When you become bigger and you’ve reached greater author success,” Kris says, “it might be a good idea to buy a block of a 100 or 1,000 for administrative purposes, especially when dealing with all the different formats (digital, print, audio, etc.).”

At that point in your success you might consider using ISBNs as you go forward, but you could just as well assign ISBNs to your existing books. Although switching your ISBN down the road does have its downsides, which we’ll detail next.

Downsides to buying your own ISBN

Something to consider, if you’re thinking of going the route suggested above, is that switching your ISBN at a later date will have an impact on your sales ranking and your reviews on the various vendor sites.

Basically, to the inventory systems of the world—Apple, Amazon, Barnes & Noble, Kobo—your ISBN is your book. So getting a new one after using one provided by a vendor or distributor will effectively start your book back at zero.

All of the data associated with your book starts over with the new ISBN. The old data is still there, and still linked with your book’s title and with you as an author, but for all intents and purposes it’s associated with a different book. Sales and reviews for the book with your new ISBN will start from scratch.

That may at first make it sound much more attractive to go ahead and start with your own ISBN. But consider this …

Having your own ISBN, rather than using one provided by a vendor, can often impose restrictions on your distribution.

This means that buying your own ISBN can restrict your ability to go wide in some cases. CreateSpace, for example, locks you out of some of their expanded distribution channels, such as libraries and academic institutions, if you use your own ISBN instead of one they provide.

Another point of consideration, especially for authors in the US, is added overhead.

New authors already have enough overhead to worry over. There’s the cost of having your book edited, the expense of having a cover designed, the cost of layout, and then all those marketing dollars.

It’s easy enough to overwhelm even a robust budget with just the ‘everyday overhead’ an author deals with. Add to that the cost of buying ISBNs on a case-by-case basis ($125 each at the time of this writing, or you can buy them at bulk at 10 for $250), and that’s a lot of extra cost for something that nets you no real benefit from the start.

Why do authors think they need to purchase their own?

Earlier we mentioned that changing your ISBN will effectively reset you to zero in terms of book reviews and sales rank. This is because the various inventory systems treat each ISBN as a separate book. So while your book with a free ISBN may have been highly ranked, with hundreds of reviews, once you replace that with an ISBN you’ve purchased from Bowker (or elsewhere, if you’re outside the US) these systems think it’s a brand new book, with no history.

That can make things a little tougher for tracking and even promoting your book with the various vendors, but it actually has no impact on something else a lot of authors covet: The bestseller lists.

But it’s a misconception about these lists that makes some people cautious.

Many authors think that if they list a book on Amazon and through Draft2Digital, and maybe through a direct account with some vendors, all using different ISBNs, then when it comes to the USA Today and New York Times Bestseller Lists those sales won’t be connected. The fear is that they’ll have sales separated by three different ISBNs, diluting their overall figures and hurting their chances of hitting any given list.

Fortunately for everyone, this isn’t true.

There is no benefit in marketing a book with your own ISBN over an ISBN assigned to your book, or even over an internal stock number provided by a large vendor. 

Book sales are reported based upon the book title and author name combination. The lists make no use of ISBNs, and now factor multiple versions of a book into its overall sales.

So long as the file you have uploaded across all platforms uses the exact same title and author name, all sales are reported for that book regardless of the identification number used to list it.

Some ISBN facts to keep in mind

We’ve expelled a few ISBN myths, so let’s look at some of the facts:

  1. If you provide your own ISBN, you need to provide it at the time of publication. For example, we often see authors who set up their book for preorder but do not provide the ISBN at the time of setup. Later, when they return and ask us to add their ISBN to the book we’re unable to do so. The book already has a unique identifier at that point, and it can’t be changed. So the important lesson: If you’re going to provide your own ISBN, you need to do it before you click Publish My Book.
  2.  Not all vendors allow a user to search by ISBN. Typically, this applies to subscription services, but some of the downstream partners of Kobo and Tolino do not support ISBN search either, so an ISBN is irrelevant for these vendors. As time goes by this is becoming more common. Vendors tend to prefer their own internal inventory systems, and so paying for an ISBN ends up being an unnecessary expense.
  3. Make triple sure that you apply the correct ISBN the first time. We can’t tell you how many times an author has uploaded multiple books in one sitting and accidentally mixed up some of the ISBNs. This causes major headaches for the authors and vendors alike, and can sometimes result in the ISBN being completely burned at one or more vendors. Once a book is published, it’s nearly impossible to change the ISBN, so authors should take extra care when providing their own.
  4. Different physical formats definitely do require different ISBNs. We discussed above why you might not need separate ISBNs for each of your different digital formats, but you would also need separate ISBNs for the paperback, the audiobook, and the eBook. You cannot use the paperback ISBN from CreateSpace to track the eBook that you upload to D2D. We know we said this earlier, but it’s that important.

Consider the reader

When was the last time you searched for a book by its ISBN? Chances are pretty good that you never have (it does happen, though—especially for textbooks—but outliers hardly make the rule).

The reality is readers do not typically search for a book by its ISBN. Knowing the author’s name and the title of the book are usually enough. In fact, just the title is usually sufficient.

Given that, ISBNs have become a relatively pointless expense, especially when you can have one for free.

There are counterarguments to this, obviously. Some will point out, for example, that the publisher of record for your book will be CreateSpace or Draft2Digital or Ingram Spark—and that’s true. If it’s important to you that your book is listed under your own publishing imprint, then buying blocks of ISBNs would certainly be the way to go. This particularly applies to non-fiction publishers, who may publish more than one author or may want some brand uniformity among their titles.

For most authors, however, there seems to be no real disadvantage to having a book listed as ‘Published by Draft2Digital’ or anyone else. Readers pay no attention to who published the book, in the majority of cases. And it’s the readers we’re focused on most, isn’t it?

In the end, deciding whether or not to purchase an ISBN will come down to how well you can justify the expense versus how much benefit you expect to receive. In other words, it’s really up to you whether you want to make the investment.

From our perspective, ISBNs are a holdover of a system that’s becoming increasingly antiquated, and they’re unjustifiably expensive for authors. In the end, we’d recommend against buying an ISBN, especially when you’re just starting out.