International Standard Book Number (ISBN) Tips

An ISBN uniquely identifies one edition of a book released by a specific publisher in a specific format. Common formats include hardcover, trade paperback, mass-market paperback, Kindle ebook, EPUB ebook, and PDF ebook (also called Glassbook). In general, a separate ISBN from the publisher is required for each title in each format.

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In the United States, R. R. Bowker is the issuing agency for ISBNs.

Number Codes

Newly assigned ISBNs have 13 digits. The leftmost digits (prefix) identify the country (or language group) and the registrant (publisher). The remaining digits identify the book, followed by a check digit (to ensure accuracy). ISBNs may not be shared between publishers. If rights to a book are transferred from one publisher to another, a different ISBN from the new publisher will be necessary.

Older-format ISBNs had 9 and then 10 digits. Some booksellers today still use 10-digit codes for internal inventory control or cataloging. The shorter code must be calculated from, not just truncated from, the 13-digit code.

The barcode printed on or inside a book cover is EAN-13, which encodes the ISBN and may also include the publisher’s suggested retail price. Bowker sells barcodes as files that can be inserted into cover designs.

A book’s ISBN is not the same, and is not used in place of, its Library of Congress Control Number (LCCN), which many libraries and academic institutions use for indexing.


If you are not a self-publisher (or have your own indie publishing imprint), the publisher of record will provide the ISBN.

If you self-publish books using your own imprint (in the U.S.), you will have to buy ISBNs from R. R. Bowker. Even though you can purchase a number as a single lot, the next lot size is 10, which is advisable (and considerably less expensive), even if you have just one title as of now. That’s because you will need separate numbers for different formats. As well, if you have a publishing imprint, it’s likely you will eventually publish more than one book, and you can retain the numbers until you need them.

Some Exceptions

Even if you self-publish, there are some notable exceptions to buying ISBNs for your imprint:

  • If you publish a print-on-demand (POD) book with Amazon CreateSpace, you may obtain the ISBN from CreateSpace and it will be shown as the publisher of record. Note that, for the title to be eligible for some (not all) of Amazon’s expanded distribution plans, it must have a CreateSpace ISBN.
  • If you publish an ebook using Amazon Kindle Direct Publishing (KDP), an ISBN is not required. The Amazon Standard Identification Number (ASIN) assigned automatically by KDP becomes the internal Amazon stocking number. If you do use your own ISBN for Kindle, an ASIN will still be assigned and the book may be searched by either number in the Amazon online catalog.
  • Smashwords will provide an ISBN for your ebook if you publish with them, or you may specify your own. If you use the provided ISBN, Smashwords will be shown as the publisher of record.
  • If you use a paid publishing service that handles both book production and distribution and that company provides you with an ISBN, the publisher of record is that company, not your imprint.
  • The ISBN’s association with a specific publisher does not, in itself, prevent you from publishing elsewhere. (Contracts may do that, though.) However, just remember the rule that releasing the same title from a different publisher (including your own imprint) will require a new ISBN that has a prefix owned by that publisher.

Ownership of an ISBN does not imply ownership of copyright. The copyright owner is always in control of how the book is published, unless those rights are sold or licensed to someone else.


The information on this page is intended as a nontechnical summary for your project planning. Always check with appropriate authorities for current and detailed information before making any final decisions.


International Standard Book Number, Wikipedia


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