An ISBN, or International Standard Book Number, is a unique identifier for a book that’s issued by an ISBN registration agency.
If you provided the ISBN for a book, you can find it in the book catalogue or in your book’s Metadata tab. 
  • For printed books: A 'P' is included after the ISBN for paperbacks and hardcovers.
  • For digital books: Letters that aren’t part of the identifier are included after the ISBN.


An ISBN isn't required to submit a book to Google Books, or to sell a book on Google Play. We assign a unique identifier with the prefix GGKEY to any book that doesn't already have one. GGKEYs are only used internally within Google.

10-digit and 13-digit ISBNs

We accept both 10-digit and 13-digit ISBNs. If you enter a 10-digit ISBN, the Partner Centre displays the 13-digit ISBN for consistency.

Valid and invalid ISBNs

The last digit of any ISBN is a 'check digit', which is generated by a complex calculation performed on the other digits. If this digit doesn't match the result of that calculation, the ISBN is considered invalid and the Partner Centre won’t permit you to create a book with it. 

Legacy 10-digit ISBNs have a 13-digit equivalent that begins with 978, followed by the first 9 digits of the 10-digit ISBN.

For more information on check digits, go to the ISBN Wikipedia entry.

Partners using ONIX

When ISBNs are for the digital version of books, we only accept eBook prices provided by ONIX.

Multiple ISBNs for a book

Different editions of a book may have different ISBNs. You can add each ISBN as a separate entry in your book catalogue. To minimise the number of entries, we recommend that you use one of the following methods to indicate multiple ISBNs.

Method one: A single entry with a primary ISBN and related ISBNs

We recommend that you only add the book to your book catalogue once. Select a primary ISBN and add any related ISBNs in the About the Book tab. 

For example, if you have a book with different ISBNs for paperback and hardcover editions, you can use the paperback ISBN as the primary ISBN and the hardcover ISBN as a related ISBN.

Our system uses the primary ISBN in the following ways:

  • The primary ISBN is displayed in your reports. 
    • If you sell books on Google Play, sales reports display the primary ISBN and one related ISBN.
  • Google Books preview pages include links to purchase your book. These links lead to pages specific to your primary ISBN.

A single primary ISBN works best for:

  • A book that you don't plan to sell on Google Play
  • A print-only book with different ISBNs for paperback and hardback editions
  • An eBook with no print edition and different ISBNs for different electronic formats, such as .epub and .pdf
Method Two: Two entries for the print and electronic editions

To sell a book that has different ISBNs for print and eBook editions on Google Play, you can add two entries to your book catalogue:

  • Print edition ISBN or 'pISBN'
  • Electronic edition ISBN or 'eISBN'

This dual setup is more complex but offers these benefits:

  • Google Play sales reports display the eISBN.
  • The Google Books preview page for the pISBN entry includes:
    • Links to purchase the print edition of your book
    • A 'View eBook' button that goes to the page for the eISBN entry

We recommend that you add two entries when all of these circumstances are true:

  • You want to sell the book on Google Play.
  • The book has different ISBNs for print and eBook editions.
  • Google Play sales reports should use the eISBN.
  • You want the 'Buy this book' link on the Google Books preview page to point to the print edition.
To use two entries for print and electronic editions:
  1. If you have multiple pISBNs or multiple eISBNs, select a single primary pISBN and a single primary eISBN. You can enter additional pISBNs or eISBNs as related ISBNs.
  2. Activate the pISBN entry to go live on Google Books only. This setting prevents confusion about which edition to buy on Google Play, since  only the eISBN entry is available for sale.
    • The primary ISBN for this entry is for the print edition.  Links to buy the book on the Google Books preview page take users to pages specific to the print edition.
  3. On the pISBN entry, list the eISBN as a related ISBN of the type 'Electronic version available as'. This setting generates a 'View eBook' button on the Google Books preview page that will lead to the book's page on Google Play.
  4. Enable the eISBN entry for sale on Google Play.
  5. Provide prices and sales settings for this entry.
  6. On the eISBN entry, list the pISBN as a related ISBN of the type 'Epublication based on'. This setting allows someone to use the pISBN to find your book in the Play Store.

Instructions for partners using ONIX

Step 1:

Use the relatedproduct module to list the eISBN with RelationCode 27.
  <RelationCode>27</RelationCode> <!-- label indicates digital (eBook) ISBN (eISBN)-->
    <IDValue>9780312945077</IDValue> <!-- 13-digit digital (eBook) ISBN (eISBN) -->

Step 2:

Use the relatedproduct module to list the pISBN with RelationCode 13.
  <RelationCode>13</RelationCode> <!-- label indicates print ISBN -->
    <IDValue>9780312945077</IDValue> <!-- 13-digit print ISBN -->


  • If you have both a .pdf file and a .epub file for the book, submit the .pdf file under the pISBN entry and the .epub file under the eISBN entry. 
  • If the two entries are linked with reciprocal-related ISBNs, both formats are available to people who buy the book on Google Play. The original printed page numbers display, even in flowing text mode.

Summary of recommendations for submitting two entries for print and electronic editions

pISBN entry eISBN entry
Activated to go live on Google Books Enabled for sale on Google Play
eISBN listed as a related ISBN of type 'Electronic version available as' pISBN listed as a related ISBN of type 'Epublication based on'
Book content provided in .pdf format Book content provided in .epub format
File named pISBN.pdf* File named eISBN.epub and cover file named eISBN.jpg*

* Replace pISBN and eISBN with the actual ISBN

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