What is an ISBN


“What was the name of that book you wanted?”

“Oh, it’s called ‘Contact,’ I think!”

It would be hard for you to glean much from this conversation. Is this the book title of a new sci-fi thriller set in some distant, far-flung galaxy? A history of martial arts? Or maybe the biography of New Zealand’s greatest rugby star?

Of course, the mystery book could be any of these. With only so many words to go around, very different books frequently end up sharing the same title. And that can lead, inevitably, to some confusion.

Booksellers and book buyers need to be sure they can find the right book when they need to. That way, Uncle Joe – sci-fi fan – won’t end up with a book about rugby this Christmas.

ISBNs help.

What is an ISBN?

The International Standard Book Number (ISBN) is a 13-digit product code. It’s assigned to every book to help publishers, distributors, retailers and libraries easily identify it from other books.

The 13 digits aren’t random. Each part, separated by a hyphen or space, represents something different, including the global region or language, the publisher who owns the ISBN, and the book number.

For example, we can immediately tell that the example below is an English book because the fourth digit is 1. If you’re curious about what the other numbers mean, then have a look at this article.

What is an ISBN

Does my book need an ISBN?

If you plan to sell your book anywhere then yes, it does.

There’s no legal requirement to have an ISBN, but books do struggle without one. ISBNs work with retail systems to make buying and selling your book much, much easier.

If you only plan to give out copies to friends and family, then it’s less important, but if you’d like to distribute any further than that, an ISBN is essential. It’s extremely unlikely a bookstore, library or online retailer will even stock your book without an ISBN. They simply wouldn’t be able to scan and identify it, and that’s far too much trouble all-round.

We’ve established that an ISBN uniquely distinguishes your book from others with the same or similar title. However, retailers also use ISBNs to differentiate between different editions of the same book.

That means you’ll need to allocate an ISBN to each different format of your book. So, if you intend to sell your book as a hardback and later as a paperback, you’ll need to order two ISBNs, one for each type.

What about my ebook?

The ebook version of your book is a different format, and so, yes, that will require its own ISBN, too.

However, of the two main ebook formats – epub and Mobi (Kindle ebooks) – it’s only really worth allocating an ISBN to the epub version.

That’s because only Amazon sell Kindle books, and Amazon ignores the ISBN to assign their own system: an ASIN (Amazon Standard Identification Number). All other major ebook retailers of epub versions, (like Apple, Google, Nook, Kobo), on the other hand, use ISBN numbers as normal.

What if I have a new edition?

You can make a few minor changes and corrections to your book without changing the ISBN. However, if you decide to make substantial changes to a published book, you should always allocate a new ISBN to the revised edition.

It is something of a fuzzy area, but generally, we’d consider a major revision to be inserting a lot of new material, deleting major elements, or publishing the book in a different language. All these things alter the reader’s experience enough to make giving the book a separate identity, in the form of a unique ISBN, extra important.

How do you get an ISBN?

An agency is appointed to sell ISBNs in every country. In the USA, that agency is Bowker, and in the UK, it’s Nielsen. You can find your agency and further instructions by visiting the ISBN Agency website.

When ordering an ISBN, you’ll need to provide certain details about your book, including the trim size and final page count.

This can feel frustratingly like a chicken-and-egg-scenario. Your typesetter may ask for your ISBN number, but until they’ve typeset your book, how do you know how many pages to enter for the ISBN registration?

Don’t worry. At this point, just give your best guess, and once your book is complete, you can simply update the ISBN information. Remember to update it again with any future changes such as a price reduction, too. ISBNs create a digital fingerprint of your book’s life, and so you’ll need to keep your agency informed of all your book’s up-to-date information. It’s just like letting a database know if you change your name or move house!

How much is an ISBN?

It’s your country’s agency which sets the price of an ISBN. Some countries, like Canada, issue them for free but, in most countries, the price of an ISBN heavily depends on how many you buy. For example, Bowker currently charges $125 for a single ISBN, $295 for 10 ($29.50 each) and $575 for 100 ($5.75 each).  So even if you’re only planning to publish a single title, it’s probably worthwhile buying a block of ISBNs for different formats or future editions. And since they never expire, you can always hang on to any leftover for your next book!

What do you do with an ISBN?

So, once you have an ISBN, what do you do with it?

There are two places this number needs to appear: the copyright page and the back cover.

On the copyright page, you should simply list the digits of the ISBN in blocks, separated by dashes. If you have multiple formats of the same title, such as a paperback and ebook, then it’s also a good idea to list both ISBNs with a description next to each. This helps readers to quickly see that there are multiple formats of your book available and make a choice about which they might prefer.

On the back cover of a book, the ISBN is typically used to create a barcode. The digits of the ISBN can be used to generate the barcode lines. Retailers can then scan the unique black striped rectangle to monitor sales and manage their stock.

And the last word …

So there you have it. That inconspicuous number on the back of your latest favourite paperback is doing a more important job than you realised.

Gifting your book with an ISBN is one of the best things you can do to equip it for life out in the world. An ISBN will help your book to be found, sell, and shared by people excited to spread its message.

Who knows? Those crucial 13 digits might even help your book to end up in Uncle Joe’s next Christmas stocking. We mentioned that Uncle Joe, was a movie producer, right?