View Shopping Cart
Shopping Cart / Checkout | About Judy Cullins | Contact
Return Home Subscribe to Judy's RSS Feed
FREE Subscription: Why subscribe? | Privacy Practices

Do I Really Need a Separate ISBN for my eBook?

by Ron Pramschufer

I can recommend Ron Pramschufer’s approach to self publishing. He also has a great newsletter you must check out!

This is probably one of the most asked; least understood questions out there in the self-publishing world today. Technically you not only need an ISBN but you need a different ISBN for each format your ebook is being offered. If you are offering your book as a mobi, epub and a PDF, you need three different ISBNs. That’s technically. In reality, if you are only making your eBook available on Amazon, you don’t need any. Confused?

If you think about it a minute, it makes sense. If an ISBN is like a fingerprint, every different edition of your book needs a separate set of fingerprints (ISBN) to identify it. The easy one to understand is paperback and hardcover. They are obviously different editions. When a person purchases the paperback version of your book, that is what they expect to receive. The ISBN is what identifies the format. How about if the paperback book version was the tradebook size of 6 X 9. Let’s say you get an inquiry for the mass market paperback size of 4 ¼ X 7. Do you think you would need a new ISBN for the mass market size? Of course you would. How else would know which book was being ordered? So in reality, it is not one for the paperback version and one for the hardcover. It is one for each format. A 4 ¼ X 7 paperback is a different format from a 6 X 9 paperback, thus a different ISBN is needed.

Now let’s think about eBooks for a second. You need a separate ISBN for your eBook, right? Makes sense, doesn’t it? You wouldn’t want someone to order a paperback book when they really wanted an ebook. How do you tell the difference between the two? The ISBN, of course. Now let’s take that one step further. I want to buy an eBook to read on my Kindle. The file type that works on a Kindle is a Mobi file. I also want to buy the same book for my IPad. The IPad takes an ePub file. How do you think the store tells the difference between the two? What would happen if both versions has the same ISBN? It would be just like the trade paperback, mass market paperback situation. If it’s a different format, it needs a different ISBN. That’s the official story… Now the reality story for 99% of the self-publishers.

Amazon has its own numbering system called ASIN. The ASIN number for Publishing Basics-Navigating the Self-Publishing Minefield is B003Y8XR0K. Amazon uses the ISBN like window dressing. If you go to the eBook upload link at Amazon, the spot on the form that says ISBN, also says “Optional”. IE: You don’t need one for Amazon. Amazon is the only place that uses a Mobi file… Amazon has their own numbering system…therefore your Mobi file does not need a separate ISBN. Will the possible eBook formats remain at two? Fat chance. Do I suggest that you run out and buy a 100 block of ISBNs so you can be “ready”? NO. I suggest you purchase one and apply it to the ePub file.

Please keep in mind that I am only barely beyond “lukewarm” with this whole eBook “phenomenon”. While I am seeing more people on the train with IPads (might get one myself just for the 8 hour battery), but I see them mostly as a replacement for laptops… not a replacement for books. I’m still waiting for the $2 that Amazon owes me for my eBook sales.

As you probably know, I sell single ISBNs for RR Bowker for $99, if you printed with me. I also sell eBook conversions for $129, if you did your original book layout with me. That $228 gets you a Mobi file and an ePub file. The ePub file will contain the new ISBN. $228 is just about the limit of what I would recommend the self-publisher spend on his venture into the eBook world. My opinion on this could change, similar to the way it has changed towards basic POD distribution, but for now… this is where I stand.

I asked my friend at RR Bowker if she could send me the “official” word from the ISBN agency as it pertains to the subject. I have made it available below. I want to thank all my friends at RR Bowker, the US ISBN agency for their help with this and all our other ISBN matters. In the end, you are the publisher and ultimately responsible for how you handle this. Happy eBooking!! – Ron

Guidelines for the assignment of ISBNs to e-books and “apps”

ISBN is an identifier of monographic publications (books) and related products available to the public. ISBN should not be used to identify files that only pass between publishers and typesetters or e-book conversion services, nor should it identify abstract entities such as textual works (content).

Publications need separate ISBNs if anyone in the supply chain needs to identify them separately.

End users need to know a) whether the e-book that they are purchasing will work on their device or software and b) what they will be able to do with it (e.g. copy, print, lend etc.). This is normally defined by a combination of file format and Digital Rights Management software. Separate ISBNs will facilitate management, dissemination and discovery of that information as well as delivery of the appropriate version of an e-book.

Separate ISBNs also facilitate the listing of various e-book versions in trade databases, sales and usage reporting and e-commerce transactions, especially where multiple formats are sold through the same channel.

FAQs for publishers and intermediaries

1. If I publish in two or more different file formats (e.g. epub, PDF) should I assign separate ISBNs?

Yes. Each different format of an electronic publication that is published and made separately available should be given a separate ISBN.

2. Should different versions of the e-book that use the same file format (e.g. epub) have different ISBNs?

If the different versions use the same DRM software (e.g. Adobe ACS4) with substantially the same settings and are interoperable on different devices or software, then a single ISBN should be used. If, however, the same DRM software is used on two versions but with significantly different settings (e.g. one allows printing but the other does not) then each version should have its own separate ISBNs.

If proprietary DRM is used that ties a version to a specific platform, device or software then, if ISBNs are assigned (see 6 below), separate ISBNs should be used for each such version.

3. Assuming the same content, what are the features that distinguish different e-book products and determine whether separate ISBNs are required?

The key features are whether any specific device or software is required to read the e-book and what user functionality is provided (e.g. copy, print, lend etc.). As mentioned above, this is normally defined by a combination of file format and Digital Rights Management software.

4. Is there a standard way of describing different product forms and DRM features?

ONIX for Books is the international standard for representing and communicating book industry product information in electronic form. The latest release, 3.0, has improved handling of digital publications and provides structures for describing product form detail and DRM usage constraints. Even if you do not use ONIX, you can use the standard codes to describe product form and usage constraints listed in the relevant sections of code lists version 12 (DRM–related codes, lists 144-147; product content type, list 81; product form detail, list 175).

Further information on ONIX for Books 3.0 and code lists is available at

5. If I provide a single master file to a conversion service and am not controlling the different combinations of file format and DRM provided by that service to retailers, should I assign an ISBN to that master file?

No, unless it is also being made available to the public in exactly the same form as your master file (i.e. unchanged file format and without DRM applied). You should assign separate ISBNs to each version generated by the conversion service (see also question 6 below). If your legacy computer system requires an ISBN to identify a master file, then this should be kept as a purely internal identifier to avoid the possibility of several different versions carrying the same ISBN.

6. If my e-books are being supplied by a retailer that is the sole provider of e-books in a proprietary format that can only be bought it‘s own website (e.g. Amazon Kindle, Apple i-bookstore) and that retailer does not require ISBNs, should I assign ISBNs to those versions?

It is not necessary to do so, unless it is useful for your own purposes or you want that version to be listed in third-party databases of available e-books . However, since these platforms are generally not interoperable, if you do assign ISBNs, make sure that they are unique to each version to avoid problems if those versions should later become available through third parties.

7. I provide an e-book conversion service to publishers but they are not providing separate ISBNs for each version that I generate. What should I do?

If a publisher will not provide ISBNs to intermediaries for this purpose then, as a last resort, intermediaries may assign their own ISBNs. ISBN agencies will provide ISBN prefixes to intermediaries for this purpose. In this case ISBNs and related metadata should be provided back to the publisher and to the national ISBN agency and other bibliographic agencies.

Note that the assignment of an ISBN has no implications for rights ownership.

8. E-book reading devices offer different features such as type size, text to speech, bookmarking, colour etc. Although my content, file format and DRM are the same, the user experience varies according to the device used. How does this affect the assignment of ISBNs?

If the content, file format, DRM and settings are unchanged, then any variation that depends on the device or software used to read the e-book does not impact on the ISBN.

Note that provision of mono or colour images in separate e-publications intended respectively for mono or colour devices constitutes a change of content – and therefore of ISBN. However if colour images only are provided, but a particular device has only a mono display, that is simply a device limitation and does not imply a second ISBN.

9. Should an enhanced e-book that includes audio, video or other additional content have a different ISBN from the standard e-book.

Yes. Since there is extra content included in the enhanced e-book it is clearly a different product and should therefore have a separate ISBN.

10. Can e-book “apps” (e.g. applications for iPhone, Android etc.) have ISBNs?

Yes, provided that there is significant textual content. An e-book app is simply a combination of textual and other content and software. If the software element is different (e.g. targeted on different operating systems), then each version should have a separate ISBN. However, please see question 6 above. If the app is only being made available through a single source, then ISBNs may not be necessary.

11. I am publishing two versions of an e-book, one without DRM and one with ‘social’ DRM that does not enforce any restrictions on the user (e.g. watermarking). Do I need two separate ISBNs?

No. If the social DRM does not enforce any restrictions or intrude significantly on the users’ experience, it is transparent to them and need not be given a separate ISBN.

12. How can all the different versions of an e-book be linked together?

The ISTC (International Standard Text Code) is a new ISO identifier that identifies the underlying textual content of the book and is therefore shared by all digital and physical manifestations of the same title. The assignment of ISTCs would facilitate the linking of all versions and, with the addition of a filtering element such as product form, could also be used to link all e-book versions. Some systems already use an internal work identifier to provide this functionality but this cannot be used in the supply chain.

Note that the implementation of ISTC also facilitates the“inheritance“ of metadata from work level to manifestation level and can save rekeying.

Further information on ISTC is available at

13. How do I identify individual chapters or other parts of a book that I plan to make available separately?

If you are making chapters or other parts of a book separately available through the normal supply chain and want to have them listed in trade databases then you should regard them as individual publications and assign ISBNs to them. If they will only be available through a single source, such as the publisher’s website, then proprietary internal identifiers will be adequate.

International ISBN Agency – November 2010

For further information please contact [email protected]

Remember, you’re self-publishing. – Ron

Ron Pramschufer has been in or around the printing and publishing industry for over 35 years. His—named one of Writers Digest’s, 101 Best websites for writers for 2006—has helped thousands of customers print over 105 million books. Write to Ron at [email protected].

Related Posts Plugin for WordPress, Blogger...
About the Author, Judy Cullins

Book and Blog Coach Judy Cullins helps you gain confidence and transform your ideas into life-long money-making content. Author of 14 books for business people and authors include “Write your eBook or Other Short Book–Fast!”Judy offers free, up-to-the minute weekly publications on book and blog writing and online marketing at

*You are welcome to reprint this article provided the above bio is included.

Published by Judy Cullins

Never Miss a New Post! Subscribe to our website and our RSS Feed today! 🙂

  • patriciacarrigan1

    This was a very informative post. I’m sure many authors will be very glad to have this available to them!

    Thanks so much!

    Patricia Carrigan
    Author Antiserum

  • Saul Bottcher

    Lots of good information in this post.

    At this point (June 2013) the e-book industry outside of Amazon is essentially standardized on EPUB format, so a single ISBN for your EPUB is sufficient for a self-published author.

    If you’re in the U.S., you don’t actually need to go through Bowker for your ISBNs. You can get ISBNs as low as $20 or even free by having them assigned by a Canadian service provider. Take that $100 you just saved and put it into promotions or more polished production for your book!

    For some more answers to common ISBN questions, authors might want to refer to this article I wrote:

    I cover a few questions such as “What is an e-ISBN?”, “If I update my book, do I need a new ISBN?”, and “Does an ISBN affect copyright and/or ownership or my book?”.

    Hope this information helps. Good luck to everyone in their self-publishing endeavours.