ISBNs in the UK: do you need one, and who should own it?

An ISBN (International Standard Book Number) is the 13-digit number that identifies a particular edition of a book. Booksellers, libraries and distributors use it to find, order and track your book. For authors who publish themselves, the practical questions are: do I need one, who should hold it, and what comes with it?

Do you need an ISBN?

• Print books sold through bookshops and libraries: yes. Retailers and distributors expect one.
• Print books sold only on Amazon KDP: KDP can assign one for free, but read the next section before you accept it.
• eBooks: Amazon does not require an ISBN for Kindle eBooks, but many other retailers and platforms do, and having one gives you a consistent identifier across stores.

Each edition needs its own number. A paperback, a hardback and an eBook are three editions, so they take three ISBNs. A new edition with significant changes also takes a new one.

Where UK ISBNs come from

In the UK, ISBNs are issued by Nielsen ISBN Agency. They are sold singly or in blocks, and the person or organisation that buys them is the registrant. Check the agency's current pricing and rules, as both change.

Why ownership matters

The registrant is recorded in the book's metadata as the publisher. That has real consequences:

• If a free ISBN from a platform is used, the platform is shown as the publisher, and the number can only be used on that platform.
• If you use your own ISBN or your imprint's ISBN, your imprint is shown as the publisher, and the number travels with the book across retailers.
• If a service provider's ISBN is used, the provider is shown as publisher of record, even though you remain the author and, if the agreement says so, the owner of the rights.

None of these is wrong. They do different things, so choose knowingly. At Fable Studio, you can publish with an ISBN registered to your own imprint, or with ours. If we use ours, we are listed as the publisher in the book's metadata, but that gives us no rights in your book, and we explain the options before anything is set up.

Common ISBN mistakes

• Using one ISBN for several formats. Each edition needs its own number.
• Accepting a free platform ISBN without thinking it through. It can tie that edition to one platform and name the platform as the publisher.
• Not keeping a record. Write down which ISBN belongs to which edition, and when you assigned it.
• Mismatched details. The title, subtitle and author name on the copyright page, the cover and the retailer listing should match what is registered. Our guide to book metadata explains how to keep them consistent.
• Changing a book substantially without a new number. A significantly revised edition needs a new ISBN.

If you are not sure which formats you need, see paperback, hardback or eBook.

Common questions

How many ISBNs do I need? One for each format of each edition. A paperback, a hardback and an eBook are three. If you expect several formats, a revised edition or a second book, a block of ten usually costs less per number than buying singly. Check the current prices in the Nielsen ISBN store.

Do ISBNs expire? Nielsen states that unused ISBNs stay valid indefinitely.

Who should I buy from? In the UK, ISBNs are allocated by Nielsen ISBN Agency. An ISBN should be registered in the name of whoever publishes the book, so buying from the agency directly avoids any doubt about who holds it. Be careful with resellers.

Can I move a book to a different ISBN later? You can publish a new edition under a new number, but an ISBN stays registered to whoever bought it, and a new number means a new listing. That is why it is worth deciding who the publisher of record will be before you start.

Barcodes

The ISBN is turned into a barcode on the back cover. Your cover designer needs the ISBN, the price information if you want it shown, and the final page count so the spine width is right.

Legal deposit: the duty most new publishers overlook

Under the Legal Deposit Libraries Act 2003, the publisher of a printed book published in the UK must deliver a copy to the British Library, free of charge, within one month of publication. Five other legal deposit libraries can request a copy in writing within 12 months of publication, usually through the Agency for the Legal Deposit Libraries, and the publisher must supply it within one month of the request. eBooks and other electronic publications are covered by separate regulations. If you are the publisher of record, this duty applies to you, so check the current guidance on the British Library's website and keep a copy of the delivery.

A quick checklist

1. Decide who will be the publisher of record.
2. Get one ISBN per edition.
3. Keep your ISBN records somewhere safe.
4. Put the correct ISBN on the copyright page and the cover.
5. Arrange legal deposit for UK print editions.

Whichever ISBN you choose, a book we launch is published through your own distribution accounts, and retailers pay your royalties directly to you. See independent assisted book launch.