Answered By: Elizabeth Ponder
Last Updated: Nov 26, 2018     Views: 2637

The ISBN (International Standard Book Number) is a unique, commercial book identifier. ISBNs come in 10-digit and 13-digit formats. The 13-digit codes were introduced in 2007 and so most new books will have this 13-digit code that begins with the digits 978.


Typically, you should be able to find this number on the CIP (Cataloging in Progress) page of the book which is often found directly after the title page. You can also find this information on the back cover of a book usually within or on top of a barcode. Books that are copyrighted before the 1970s will likely not have an ISBN number. Consult to locate books in library catalogs around the world and to view associated ISBN numbers.

NOTE: We frequently receive questions on how to find the ISBN number of a particular book. Due to limited staff, we are unable to respond to questions submitted related to determining the ISBN number of a book. Please consult to determine the ISBN number for a particular title.

Comments (3)

  1. The real question that most people would be asking is "How do I find the ISBN for a book that I don't have in my possession? I E if I have the title and author but need the ISBN number, where do I go to look it up? Someone said "World Cat" but, although the book I'm looking for is listed in the World Catalog, no ISBN number is listed. There must be an ISBN organization that assigns the numbers and keeps a record of them. Where do I go to access its database?
    by Jay Tyson on Sep 14, 2017.
  2. You would think that, but WorldCat is actually the best place. Books before the early-to-mid 1960s did not have an ISBN. They might have had a standard book number, but those were less than 10 digits, so not the same thing. Some books, particularly those with small press runs, those published by vanity presses, and sometimes just small publishers were not necessarily assigned ISBNs either. These days it's rare to find a book without an ISBN - or more than one since hard copy vs. paper copy are often given different ISBNs - and electronic almost always has a separate ISBN. The reason we recommend WorldCat is that it contains the catalog records used by library's around the world (including the Library of Congress), and if there is an ISBN it is standard practice to list those in the cataloging record (and all the different ISBNs for different versions). If you can't find one that way then in all likelihood there is NOT an ISBN for that book for whatever reason as we stated above. You can try the U.S. ISBN Registration office which is through Bowker. That URL is However, you would probably just as easily find out if a book had an ISBN by contacting the publisher.
    by Cynthia Peterson on Sep 15, 2017.
  3. When searching WorldCat, remember that the results for each item come up in sections. First, WorldCat gives you the general information about the particular title. Then, beneath the basic info, there is a section entitled, "Find a Copy in the Library" which lists OCLC Member Libraries which hold copies of the title. BENEATH THAT, is a section entitled "Details" which will list the ISBN and OCLC numbers for the title. Please remember that most titles have more than 1 ISBN number; In the general info section, OCLC will tell you if the item is a "Print Book" or an "eBook" and the ISBN numbers will be different for each media type. Also note that there is a tiny link next to the media type entitled, "View All Editions and Formats." You can then find which media type you want, and then scroll down to the Details sub-heading, and find the ISBN for that particular item.
    by Christopher Altnau on Aug 23, 2018.