If you are self-publishing a book, one question to ask yourself is if it is worth to get a custom ISBN (International Standard Book Number) for your book. If publishing through Amazon’s KDP (Kindle Direct Publishing) they will automatically assign one, so in this case it would not be necessary. However, if you want to publish on multiple platforms it might be worth it, as well as if you are planning to publish print books as well. (See 7 Things I Learned Self-Publishing) Be aware that this might vary from country to country; for this article, we are referring to the US system.
What is an ISBN?
An ISBN is a series of numbers that are used to identify a book. The numbers are unique to that specific book. Different editions of a book will often have different ISBNs. Any ISBN assigned after 2007 will be a series of 13 digits that links the publisher (you), title, and edition of the book.
What are the advantages of having a custom ISBN?
The main advantage is tracking book sales. Let’s say you are publishing your book on multiple platforms. Since an ISBN is associated with a specific book, the sales across multiple platforms can be tracked to that one ISBN. The New York Times bestseller list uses the ISBN number to track sales of books. If self-publishing and not using a custom ISBN, the sales will not be a cumulative tracking.
If you want the book to be sold by retailers such as Barnes & Noble or libraries the ISBN is used to identify and track purchases as sales. Books that are physically printed will need one for this reason. A source such as Books in Print provides a database of published books. This database requires the books to have an ISBN.
Another advantage of having your own ISBN is you are the publisher of your book. Since you are the one who requested the number you are listed as the publisher vs Amazon or another source.
Why Not Get an ISBN?
If you are only planning to self-publish your book as an e-book through Amazon or Apple you probably don’t need one. As of this writing, Apple does not require it and Amazon will assign an ASIN (Amazon Standard Identification Number) to identify Kindle e-books through KDP. That KDP assigned one can only be used with them. An advantage of this is that there is no additional cost for KDP to assign the number.
An ISBN is expensive. The prices currently start at $125.00 for one.
How to get an ISBN?
To apply for an ISBN for your book you can go to Bowker https://www.myidentifiers.com; on the site you will be required to register and set up an account. From that point, you can purchase just one ISBN or multiples. If you are planning to self-publish more than one book or do multiple editions, I would recommend purchasing more than one at a time to save money.
Once you purchase the ISBN you will be able to enter the book information that will be associated with that ISBN on Bowker. You can then take that number to KDP, Smashwords, or whatever other publishing platforms you are using. The platform will have a place to enter the ISBN.
Note that once the ISBN has been assigned it cannot be changed and assigned to another book at a later date. Also, if you have already self-published through KDP, the ASIN cannot be changed. This means you will need to publish your book again and enter the ISBN during the setup process. The originally published book can then be removed from Amazon. The downside of this is that those original sales won’t be tracked to the second edition of the book. On Smashwords, it is possible to assign the ISBN after publication.
If you are at all considering publishing your book on more than one platform, then I would recommend getting and assigning an ISBN. If, like many people, you are only planning to publish through KDP, then it is probably not worth the extra cost.