ISBN stands for International Standard Book Number. It is generally a 13-digit number, and it is used as an identifier for books. ISBNs are used internationally. If you plan to sell your book online (or in bookstores). You will probably want an ISBN for each book you publish.

Amazon is the only online retailer that does not require an ISBN number for ebooks. They assign their own unique identifier to ebooks called and ASN number. However, it is still strongly recommended that you have an ISBN, even if Amazon is the only store you plan to sell on. Other stores like Apple and Barnes and Noble will require an ISBN.

To get your own ISBN number go to, they are the only authorized ISBN website for the United States run by Bowker *any other source you might find online will be re-selling Bowker ISBN’s, and will likely not allow you to be listed as the publisher of record*. Click on “ISBN Identifiers” and you’ll be taken to a page where you can buy 1, 10, 100 or 1000 ISBNs. One ISBN today costs $125, but 10 ISBNs cost $250, 100 cost $575 and 1000 cost $1000. The price per ISBN drops significantly from $125 to $25 to $5.75 to $1. So, if you plan to publish more than one book it is probably worth buying 10 or more ISBN’s (they do not expire).

ISBN’s can only be registered to one book, and can only be registered one time. If you make significant changes to the content of your book (like a new edition) you will also need a new ISBN. Its recommended that you also use a new ISBN for each edition of your book. So your Print book and your Ebook editions should each use unique ISBN identifiers.

You can purchase an ISBN even if you are not a publishing company.