You can use a free ISBN provided by KDP or purchase your own from an official ISBN agency. This article explains both options and walks you through how to get and use an ISBN on KDP.

Get free ISBN from KDP

Free ISBNs are only available for paperback and hardcover books. Choosing this option means KDP will register an ISBN, using your book details, with Bowker (US ISBN agency).

To get a free KDP ISBN:

1. Go to your KDP Bookshelf.
2. Click the ellipsis button ("...") next to the book you want to add an ISBN to.
3. Select Edit Paperback Content or Edit Hardcover content.
4. In the ISBN section, choose Get free KDP ISBN.
5. Click Assign ISBN.

Note: Low-content books are not eligible for free ISBNs.

Purchase your own ISBN

You can buy an ISBN from agencies like Bowker and use them to publish a book on KDP. This ISBN can be used to publish the same book on other publishing services. Make sure it’s registered with the correct title, author name, format, and imprint (i.e. publisher name).

Bowker does offer discounted rates for KDP authors, if you'd like to buy an ISBN from them.

To use a purchased ISBN on KDP:

1. Go to your KDP Bookshelf.
2. Click the ellipsis button ("...") next to the book you want to add an ISBN to.
3. Select Edit Paperback Content or Edit Hardcover content.
4. In the ISBN section, choose Add your own ISBN.
5. Enter the details. We recommend copying and pasting directly from the ISBN agency to avoid mismatch errors.

Note: You don't need an ISBN for eBooks on KDP.

Summary of ISBN Options