ISBN stands for International Standard Book Number, and is simply a number to uniquely identify a book. It consists of either 10 digits (before 2006) or 13 digits (from 2007) and most commonly starts with 978 (although 979 also occurs).

You will find it inside the book on the Colophon page (the information page at the front of the book, with copyright details, and sometimes design and printer details too), and also on the back cover in the form of a barcode.

Not necessarily – it depends on how you want to get your book out into the world.

You DO need an ISBN:

• if you decide to independently self-publish your print book and have X copies printed to sell (for example, via your website, in local book stores, at events, or via the Amazon website)
• if you decide to publish your ebook directly on the Apple iBooks store.

You MAY NOT need an ISBN:

• if you get a traditional publishing deal – this is the responsibility of the publisher
• if you decide to publish your ebook via an online platform, such as Amazon Kindle, Barnes & Noble Nook, Kobo etc (they will assign their own unique identifier for your book)
• if you decide to publish your print book via Amazon’s print-on-demand service – this used to be called CreateSpace, but is now part of KDP (Kindle Direct Publishing) (Amazon will assign its own unique identifier)
• if you decide to publish your book via an aggregator service, to appear on multiple platforms (an ISBN is most often included in the service)

Different versions of your book will require different ISBN numbers. Depending on how you plan on distributing your book, you will need separate ISBN numbers for the:

• hardback print book
• paperback print book
• PDF version
• ePub version
• Apple iBooks version (if going direct)
• plus any (major) updates or new editions

If you decide to only publish on Amazon Kindle and/or CreateSpace, you don’t need an ISBN since they can assign their own unique identifier for you.

In Nielsen’s ISBN store, prices are as follows (for the UK, in September 2023):

• one ISBN for £91
• 10 ISBNs for £174
• 100 ISBNs for £379
• 1000 ISBNs for £979

The more you buy, the cheaper per ISBN. You may find you need several ISBNs for your book anyway depending on how you choose to distribute it (see ‘How many ISBN numbers do I need for one book?’)

For other countries, visit the ISBN International website to find out further details.

On the ISBN International website, you can find answers to many ISBN related questions. On this page you can select your country and you will find detailed information about where you can purchase ISBNs. Always check the latest information on the appropriate websites, and ensure to get all your questions answered before buying.

In the UK, you can buy ISBN numbers at Nielsen UK ISBN Agency. In their ISBN Store, you’ll find pricing information. Processing may take around 10 days, but there is a fast track option available.