The International Standard Book Number (ISBN) is a 13-digit identifier assigned to one specific edition and format of a book. Booksellers, distributors and libraries use it to order, track and catalogue your title. It is not a copyright registration and it does not prove ownership of your work.

How an ISBN is built

An ISBN-13 such as 978-1-4028-9462-6 has five parts: the 978 or 979 prefix, a registration group (country or language area), the registrant (publisher), the publication element, and a check digit. The lengths of the middle parts vary, which is why hyphens must be placed using the official range table. Browse every registration group or hyphenate an ISBN with the converter.

One ISBN per format

Each format needs its own number: the paperback, hardcover, large-print edition, ebook and audiobook are all separate products. You also need a new ISBN for a new edition with substantial changes, a new title, or a change of publisher. You do not need a new ISBN for a reprint with typo corrections or a new cover on the same edition.

Many ebook retailers do not require an ISBN at all — Amazon assigns its own ASIN to Kindle books — but using your own ISBN for the ebook keeps your catalogue consistent across stores and library services.

Where ISBNs come from

ISBNs are issued by one national agency per country or language area. In the United States that is Bowker; in the UK and Ireland, Nielsen; in Canada, ISBN Canada at Library and Archives Canada (free); in Australia, Thorpe-Bowker. Several countries — including Canada, New Zealand, India and South Africa — issue ISBNs free of charge. Buy only from your national agency or its authorised resellers; ISBNs bought from third-party resellers may list someone else as the publisher.

Free platform ISBNs vs your own

Print-on-demand platforms often offer a free ISBN. It is convenient, but the platform (or a generic name such as "Independently published") becomes the publisher of record, and the number usually can only be used with that platform. If you want your own imprint name in bookseller databases, the ability to move printers, or a professional appearance for bookstores and libraries, buy your own. Agencies sell ISBNs individually or in blocks; blocks of ten or more cost much less per number, and most authors use several over a career.

Register your imprint

When you buy ISBNs you create a publisher account. The publisher name you enter there is your imprint — keep it identical on your title page, copyright page and retailer metadata. Then assign each ISBN to a title and format in the agency's portal and fill in the metadata (title, contributors, format, trim size, page count, price, publication date).

Barcodes

Printed books carry an EAN-13 barcode that encodes the ISBN-13, often with a five-digit price add-on (for example 51995 for US$19.95, or 90000 for no price). KDP and IngramSpark can place a barcode for you; if you design your own cover, generate a vector barcode with our barcode generator and place it at 100% size, black on white.

Where to print the ISBN

  • On the copyright page, listing every format's ISBN with a label (paperback, ebook…).
  • On the back cover, above or within the barcode.
  • In the metadata of your ebook file.