Do I need an ISBN for my eBook?

This a question that comes up frequently with new authors. For many, it’s a subject that’s all too often shrouded in confusion. Depending on where in the world you come from, or what route you take to get published, obtaining an ISBN can cost anywhere from nothing to literally hundreds of dollars. In many cases, there’s only one source of ISBNs and this source is NOT cheap – especially if you are buying your ISBNs individually. If you believe you need an ISBN not only for multiple books but for multiple versions of the same book and/or for each individual format of the book (PDF, MOBI, ePub, etc.), then this can add up quite quickly. However, it needn’t be as expensive as you may have been led to believe. I’ll explain what ISBNs are for and then I’ll tackle why you need one and when.

What is an ISBN?

ISBN stands for International Standard Book Number. It’s a 10 or 13-digit number that uniquely identifies books and book-like products (think of things like physical books, autiobooks, etc.) published internationally. It’s a way to uniquely identify one book over another. There are various reasons why it’s necessary to track books and to be able to distinguish them from each other. There may be many different books that have the same title, for example. If you are searching for a book, you need a way to uniquely identify the one you want. The ISBN is one way to do this.

ISBNs have been around since 1970. The format changed from 10-digits to 13-digits in 2007. The 13-digit ISBN is broken down into multiple parts. The following description of those parts is taken from the website:

  • Group or country identifier which identifies a national or geographic grouping of publishers;
  • Publisher identifier which identifies a particular publisher within a group;
  • Title identifier which identifies a particular title or edition of a title;
  • Check digit is the single digit at the end of the ISBN which validates the ISBN

How do I obtain an ISBN?

The principal distributor of ISBNs is Bowker. Depending on which country your in, the name of the distributing body might be some variation on this name. For example, here in Australia, ISBNs are distributed from Thorpe-Bowker. If you are an independent author and publishing your book yourself, you may be able to obtain a free ISBN from whomever it is you are publishing your book through. In some countries, like Canada, you may be able to obtain an ISBN for free but in others you have to pay Bowker. Like most things, ISBNs become cheaper the more of them you buy. If you have to purchase a single ISBN through Bowker, you may be paying $125. For a block of ten, it’ll cost you $250. For $575, you can get a block of 100, and so on.

Do I need an ISBN?

This depends on what you are publishing and how you are publishing it. However, if you believe Bowker, you need an ISBN for just about every conceivable scenario. Their website states the following:

The purpose of the ISBN is to identify one specific version of a book. If you wish to have a hard bound copy, a soft bound copy, an ePUB, a PDF, a MOBI, or even register a new version, you will need a unique ISBN for each version. This allows retailers to help the customer understand exactly which version of a title they are purchasing.

This is highly misleading and may lead you to believe you need more ISBNs than you actually do. It’s perhaps not surprising given the monopoly Bowker has on ISBNs. It’s in their best interest after all to sell you as many ISBNs as they possibly can. However, you DO NOT need ISBNs for all these situation.

If you are producing a print version of your book, you will definitely need a separate ISBN for the paperback version and another separate ISBN if you intend to produce a hardback version. However, for digital books for distribution to a Kindle, Nook, iPad, etc., (hereafter referred to as eBooks), this isn’t the case at all. You most definitely DO NOT need separate ISBNs for each format of the eBook you plan to produce, such as ePub or MOBI. Why is this? Simple. The big five eBook retailers, Amazon (Kindle), Apple (iPad), Barns & Noble (Nook), Kobo and Sony don’t use ISBNs at all. They don’t track eBooks using ISBNs. Their systems are closed and don’t interoperate with the ISBN mechanism used in the physical world. Amazon, for example, will assign your eBook their own tracking number, called an ASIN, which they will use to track your eBook with instead of an ISBN. Amazon’s website has this to say about ISBNs:

An ISBN (International Standard Book Number) is not required to publish content with Kindle Direct Publishing. Once your content is published on the KDP website, will assign it a 10-digit ASIN (Amazon Standard Identification Number), which is unique to the eBook, and is an identification number for the Kindle Book on

If you already have an ISBN for your eBook, you’ll be able to enter it during the publishing process. Do not use an ISBN from a print version of your book; eBook ISBNs must be unique to eBook versions. You can purchase an ISBN from multiple sources on the Web, including the official ISBN body.

Can you buy an ISBN and use it to associate with your eBook? Sure. Is it necessary? Absolutely not – although there is one exception, which I’ll now explain.

Do I need an ISBN for my eBook?

Is there any reason at all why I should have an ISBN for my eBook? Technically, yes, but the reason is extremely weak. Apple has this to say on their website about the use of ISBNs for eBooks:

Do I need an International Standard Book Number (ISBN)?
No, an ISBN is recommended but not required for any book you are offering on the iBooks Store. An ISBN uniquely identifies the book and its current edition, and helps you to ensure that you are marketing the right book. The ISBN is also required for reporting your book’s sales to industry reporting agencies and charting organisations.

What Apple are saying is that if you want sales data to be reported to industry sales reporting agencies, then you need an ISBN associated with your eBook to enable this. That may be true enough BUT the big five eBook retailers, Amazon, Apple, B&N, etc., all have their own sales reporting mechanisms and the chances are you’re not even going to bother with the industry sales reporting mechanism. If you are going to rely on these industry reporting mechanisms, and I can’t see why you’d ever want or need to, then you will need an ISBN for your eBook. To date, I’ve not seen a compelling argument for this. My book is published through Amazon, for example. If I want to know what sales of my book are doing, Amazon provides me with a portal that provides up to the minute data. I simply cannot get that elsewhere. I don’t need an ISBN at all to take advantage of the sales data that Amazon provides.

I contacted Amazon to ask them about what requirements they have for an ISBN for eBooks. Here’s their response:

You don't need an ISBN number to publish your Kindle book. During the publishing process, Amazon will assign a 10-digit ASIN (Amazon Standard Identification Number) that will identify your Kindle book on Once you publish, you can find your ASIN under the "Title" column in your Bookshelf and in the Product Details section of your book's detail page on Amazon.

If you already have an ISBN for your Kindle book, you can enter it on the book content page when publishing in KDP. However, the ISBN will only be used as a reference. Only the ASIN will appear on the detail page for your book.

You can purchase an ISBN from multiple sources on the Web, including the official ISBN body.

We don’t require ISBNs for eBooks, but having an ISBN will ensure a lower VAT rate for sales of your book in Italy.

It seems pretty clear that ISBNs are not really needed for eBooks. It may be that Bowker and other industry reporting agencies can provide more accurate data on the state of the publishing industry overall if an ISBN was associated with every last eBook. This may very well explain why they push the angle that every version of every book needs an ISBN. However, there’s really little to no benefit to the individual author or publisher and given the exorbitant cost of obtaining an ISBN, it’s hard to see where the justification is.

The cost of obtaining an ISBN

Perhaps if ISBNs weren’t so ridiculously expensive to begin with (it is, after all, just a number), then it might not be such a big deal. In Australia, however, it costs $55 to register just for the privilege of being able to purchase an ISBN. Why is it they can get away with this? Is it because Bowker is a monopoly and you can’t get your ISBN anywhere else…and because they can? I challenged them on this point. Here’s their response:

Our registration fee is an administration charge for new publisher listings.

When a new publisher is added to our database we need to confirm, verify and edit the publisher information which has been submitted. The publisher details are then linked to all the appropriate Bowker products for maximum exposure.

As the ISBN Agency we are entitled to recover costs for the administration of ISBN applications. I think you will find that Bowker has made significant investments in developing and refining systems over the last decade which have been aimed at enhancing the discoverability and quality of metadata supporting title listings.

My Identifiers represents the culmination of that decades work and investment, which is the envy of many agencies around the world and has contributed significantly to Australian content being discoverable globally.

As part of a marketing strategy I would consider our fees to be a fair and reasonable charge.

Any information found on our website is reflective of the International ISBN Agency guidelines which states that different formats of a particular title can have an ISBN attached and for maximum exposure and discoverability we would recommend that they should.

I don’t know about you but I remain unconvinced. Someone (it isn’t hard to figure out who) is making an absolute fortune from selling very expensive ‘numbers’. It’s clearly in their best interest to maintain a demand and perhaps asserting that everyone needs an ISBN for everything is their way of doing that. I don’t buy it but I’ll let you be the judge.


So, do you need an ISBN for your eBook? No, you don’t.


I wrote this blog article in early 2017. Although all my books have been published independently, and all of the above information applies, I've since discovered a particular scenario in which an ISBN is required for an eBook. If you want your book to be published wide, I.e., distributed to all the major retailers with no exclusivity, you can upload it to all the major retailers, like Apple, Amazon, B&N, etc., manually. In that event, none of the retailers requires an ISBN to accompany your eBook. If you do this, you will need to track the progress of your book sales individually through each of those retailers. This is certainly doable but can be a bit of a hassle.

To avoid the hassle, there are a number of services that you can use to help manage everything from one place. Smashwords is one such service. You upload your book to Smashwords just once and they distribute your book to all the major retailers on your behalf. You then only need to track your book sales through the Smashwords portal, which collates sales information from each of the retailers for you. There's a catch to this. In order for Smashwords to be able to collect sales data, they insist that you attach an ISBN to your eBook. I spoke to Smashwords about this and put it to them that ISBNs are technically not needed by the retailers, so why insist that an ISBN be associated with eBooks? Here's their response:

Note that the ISBN is required for accurate sales reporting - such as what we provide on the Daily Sales and Sales & Payment Report pages - from our retailers. Because the information is provided by our retail partners and then the detailed reports are uploaded directly into our system, ISBNs allow such information to be easily and accurately tracked by our partners and then uploaded by us. As stated previously, you can claim an entirely free ISBN that we provide via Dashboard > ISBN Manager, but if you really do not want an ISBN for your books, you will need to upload to the various retail sites directly yourself, as they require ISBNs from books distributed by Smashwords and other distribution services (in contrast to publishers that are often uploading directly).

As they point out, they will provide you a free ISBN, so this will at least save you the cost of acquiring your own.

So my original conclusion still holds but perhaps I should slightly modify the original question. Do you need to buy an ISBN for your eBook? No, you don't.