← Return to contents

Considered by many the foundation stone of a book’s bibliographic data, an ISBN (International Standard Book Number) is a book’s unique identifying number.

While it is not a legal requirement for a book to have an ISBN (and some digital retailers – here’s looking at you, Amazon – don’t require one), you will likely find that you need an ISBN. It’s used:

  • by distributors, for setting up books, then for receiving and processing orders;
  • by retailers, for ordering – and this is particularly important when there’s more than one edition of the same title;
  • by libraries for acquiring titles;
  • by Nielsen, the UK ISBN agency, for tracking sales data

And so on.

So if your publishing house is solely B2C (that is, you sell only direct to customers, probably online or via print-on-demand operations) you could potentially live without an ISBN – but if you want to see your books in bookshops and you’re dealing in stock, you’ll need some ISBNs.

So what is an ISBN?

Interestingly, an ISBN isn’t just a number – it contains key bits of information that can identify a publisher as well as a title.

Until 2007 ISBNs were just ten digits long, and are often referred to as ISBN-10s or ISBNXs; now they are 13 digits long.

They are composed of five parts:

  1. the prefix for books (978/979);
  2. the registration group or country (1);
  3. the registration identifier (also known as the publisher’s prefix);
  4. the title number;
  5. the ‘check digit’, which is produced by an equation that a computer can use to check if there’s an error in the other digits.

For example, take the ISBN 9781913724009: this tells you that it’s a book, published in the UK by the publisher with the prefix ‘913724’, it’s book ’00’ (so their first ISBN), and has a check digit of ‘9’.

Different ways of writing ISBNs

So the above ISBN can be written as 9781913724009 or as 978-1-913724-00-9, breaking down all of the elements one by one, if the publisher has an ISBN book of 100.

But sometimes publishers buy ISBN books of 1000 – if this was the case then they might write the above as 978-1-91372-400-9, because this ISBN would be their 400th title, and their prefix would be ‘91372’ rather than ‘913724’.

But don’t worry – when you buy your ISBNs (from Nielsen, in the UK), they will tell you all you need to know about how to express your ISBNs.

So where do I get my ISBNs? How much are they?

In each country there is an ISBN agency who dishes out ISBNs. In the UK it’s Nielsen.

Publishers buy ISBNs in batches, and there are significant price differences; they can be bought as a one-off, single ISBN, or in groups of 10, 100 or 1,000.

At the time of writing Nielsen’s prices are:

  • Single ISBN: £91
  • 10 ISBNs: £174 (£17.40 each)
  • 100 ISBNs: £379 (£3.79 each)
  • 1,000 ISBNs: £979 (98p each)

Once bought, ISBNs do not expire; so publishers normally buy more than they need and slowly work through the list, given that a single ISBN can cost nearly 100x as much than a single ISBN in a bigger book.

I’ve bought my ISBNs – what now?

Once bought, you can allocate your ISBNs whenever you want. It’s a good idea to keep strict records of your ISBN book – either in, say, Excel or on paper – since chaos will ensue if you accidentally assign the wrong ISBN to a book. (Exaggeration? No! Bookshops will receive a different book to the one they’re expecting!)

Once you’ve assigned your ISBNs you will need to tell the world about it – and, when published, do your legal deposit so you don’t get letters from the British Library asking for books. There are many ways of doing this, and we will get into more detail elsewhere, but Nielsen will get you started with their free service Title Editor, which allows you to enter bibliographic information, which is then fed out automatically to retailers (retailers all get their information from different places, but and both receive an update from Nielsen, so information will start to appear on those sites around 24 hours+ on from entering the information).



Last updated: 1st October 2023
Author(s): Will Dady, Renard Press