Do I Need an ISBN to Self-Publish? A Store-by-Store Answer

For most ebooks, no. Amazon Kindle, Apple Books, Kobo and Google Play Books all let you publish an ebook without an ISBN. For print books, yes. Every paperback or hardcover needs one, but some platforms, including Amazon KDP, will give you one for free.

The real question is which kind of ISBN you need. A free one tied to a single platform works for many authors. An ISBN you own works everywhere. The rest of this guide explains the difference, store by store, so you can decide before you upload anything.

What an ISBN is and what it does

An ISBN (International Standard Book Number) is a 13-digit identifier for one specific edition and format of a book. Bookstores, libraries, distributors and retailers use it to order, track and list books. Think of it as a catalogue number. It doesn't prove you wrote the book or say anything about its quality.

Each ISBN is registered to a publisher. If you buy your own ISBN, you are the publisher of record, under your own name or an imprint name you choose. If a platform gives you a free ISBN, that platform (or a placeholder like "Independently published") usually appears as the publisher.

Older books sometimes carry a 10-digit ISBN. All ISBNs issued since 2007 are 13 digits. If you have an old ISBN-10 and need the 13-digit version, or the other way round, the ISBN converter will do the conversion and check the digits.

For a short definition you can bookmark, see the glossary entry on ISBNs.

ISBN requirements by self-publishing store

Here is how the main platforms handle it, based on each store's published terms. Rules can change, so confirm in the store's own dashboard before you publish.

Platform	Format	ISBN required?	What happens if you don't have one
Amazon KDP	Kindle ebook	No	Amazon assigns a free ASIN
Amazon KDP	Paperback	Yes	Use KDP's free ISBN (KDP-only) or your own
Apple Books	Ebook	No	Publish without one
Google Play Books	Ebook	No	Google assigns a GGKEY identifier
Kobo Writing Life	Ebook	No	Publish without one
Barnes & Noble Press	Ebook	No	Publish without one
Barnes & Noble Press	Print	Yes	You need an ISBN for print editions
Draft2Digital	Ebook	Optional	D2D can assign a free ISBN
IngramSpark	Print and ebook	Yes	You must supply your own, one per format
Lulu	Print copies	Optional for printing copies	You can order prints without one

The pattern is simple. Ebook-only stores generally don't need an ISBN. Print always needs one. IngramSpark is the one place where a free ISBN from another platform won't work.

How Amazon KDP handles ISBNs for ebooks and paperbacks

KDP treats ebooks and paperbacks differently.

Kindle ebooks. You don't need an ISBN. When you publish, Amazon gives the book an ASIN (Amazon Standard Identification Number). That's Amazon's internal product code, and it only means something on Amazon. There is an optional ISBN field when you set up a Kindle ebook, but leaving it blank has no effect on how the book is sold on Amazon.

Paperbacks and hardcovers. An ISBN is required. KDP offers two choices:

1. KDP's free ISBN. You click a button and KDP assigns one. Your book will list "Independently published" as the imprint. The free ISBN can only be used for distribution through KDP, including Amazon's Expanded Distribution. You can't take it to IngramSpark or any other printer.
2. Your own ISBN. You enter an ISBN you bought from your national agency, along with the exact imprint name you registered it under. The imprint must match your agency record.

For example, imagine you publish a romance novel as a Kindle ebook and a KDP paperback, and you only plan to sell on Amazon. The ebook needs nothing, and the free KDP ISBN covers the paperback. You've spent nothing on ISBNs.

Now imagine you also want bookshops and libraries to be able to order your paperback through IngramSpark. In that case you should use your own ISBN on the KDP paperback from the start, because the free KDP one can't follow you there.

The Amazon KDP publishing guide walks through both setup screens step by step.

ISBNs on Apple Books, Kobo and Google Play Books

All three let you publish ebooks without an ISBN.

• Apple Books for Authors: an ISBN is not required.
• Kobo Writing Life: an ISBN is not required.
• Google Play Books Partner Center: an ISBN is not required. Google assigns its own identifier, called a GGKEY.

Barnes & Noble Press also doesn't require one for ebooks.

If you publish an ebook on several of these stores without an ISBN, each store tracks it with its own internal ID. That works fine for selling. The trade-off is that there's no single number linking all those listings together. Library systems, some aggregators and some book databases rely on ISBNs to match editions, so an ISBN-less ebook may be harder for them to catalogue.

If you go through Draft2Digital to reach many ebook stores at once, D2D can assign a free ISBN for you. As with KDP's, it's meant for use through that service.

Why IngramSpark requires your own ISBN

IngramSpark distributes to a large network of bookstores, libraries and online retailers. That network relies on ISBNs to identify who publishes the book and where to order it. So IngramSpark asks you to provide your own ISBN for each format: one for the paperback, one for the hardcover, one for the ebook if you distribute it there.

Two points catch people out:

• A free KDP ISBN can't be used. It's registered for KDP distribution only, so IngramSpark will not accept it.
• Each format needs a different ISBN. A paperback and a hardcover of the same book are separate products, so each needs its own number.

If wider print distribution is part of your plan, buy your ISBNs before you publish anywhere. The IngramSpark publishing guide covers the setup and the cover template, which differs from KDP's.

Choosing between a free ISBN and your own

The right choice depends on where you want the book to go.

A free ISBN makes sense when:

• You're only selling through one platform, such as KDP.
• You're testing a first book and don't want upfront costs.
• You're printing personal or family copies through a service like Lulu.

Your own ISBN makes sense when:

• You want to distribute print editions through IngramSpark or other wholesalers.
• You want your own imprint name to appear as publisher instead of "Independently published."
• You plan to publish several books and want one consistent publisher identity across all of them.
• You want to be able to move a book between printers later without having to make a new edition.

The cost of buying ISBNs varies a lot by country, and in some countries they're free. Check your national agency for current prices. Many agencies sell them in blocks, which usually lowers the cost per number if you plan to publish more than one book or format. For a fuller view of what self-publishing can cost, see how much it costs to self-publish a book.

Where to buy an ISBN

Buy from the official ISBN agency for the country where you, the publisher, are based. Each country has a single designated agency (or a small number of them), and the process, price and paperwork are different in each.

A few examples, as of this writing:

• United States: Bowker is the official agency.
• United Kingdom and Ireland: Nielsen is the official agency.
• Canada: ISBNs are issued free to Canadian publishers through Library and Archives Canada.
• Other countries: your national library or a government-appointed body often runs the agency. The International ISBN Agency publishes a directory of national agencies, which is the quickest way to find yours.

Be careful with third-party resellers. Some sell single ISBNs that are registered to the reseller, not to you. The reseller then shows up as the publisher in book databases. If owning the ISBN matters to you, buy directly from your national agency.

When you register an ISBN, you'll usually enter details for the edition: title, author, format, publisher or imprint name, and often the publication date. Keep these consistent with what you enter in each store. Mismatched metadata is one of the most common causes of listing problems.

How many ISBNs one book needs

One per format and edition. A typical self-published novel might look like this:

• Kindle ebook: no ISBN needed (ASIN assigned)
• Ebook on Apple, Kobo, Google: optional
• Paperback: one ISBN
• Hardcover: a different ISBN
• Large-print paperback: another different ISBN

You need a new ISBN for a new edition with substantial changes, such as added chapters or a significant rewrite. You generally don't need one for fixing typos, updating the cover or changing the price. Your national agency's guidance will tell you where it draws the line.

Where the ISBN goes in the book

Print the ISBN on your copyright page, usually labelled by format ("ISBN 978-... (paperback)"). If you have several formats, you can list all of their ISBNs there.

On a print cover, the ISBN appears as a barcode on the back. KDP places the barcode in the bottom-right corner of the back cover for you, so leave that area clear. IngramSpark's cover template puts the barcode in its own position, which can differ from KDP's. Download each platform's template and don't assume one cover file fits both.

If you write and format your book in Inkora, the export includes ONIX 3.0 metadata and a publishing kit, and the Publishing Hub has step-by-step checklists for each store where you'll enter your ISBN. You still upload the files and enter the ISBN in your own store accounts. Inkora doesn't publish to stores for you.

Common problems and fixes

I used KDP's free ISBN and now want to use IngramSpark. You can't move that ISBN. Buy your own, then set up the IngramSpark edition with it. On Amazon you'll end up with two paperback listings unless you unpublish the KDP one and republish it with your new ISBN. KDP doesn't let you change the ISBN on a paperback once it's published. Reviews may not carry over automatically to the new listing, so check how KDP links editions before you decide.

I put the same ISBN on my paperback and hardcover. Each format needs its own number. Assign a new ISBN to one of them, update the copyright page and cover barcode, and correct the record with your national agency.

The store rejected my ISBN because the imprint doesn't match. The publisher name you enter in the store must match the name the ISBN is registered under. Check your agency account and copy the imprint name exactly, including spelling and punctuation.

I bought a cheap ISBN and the reseller is listed as the publisher. That ISBN is registered to the reseller. You can keep using it, but you won't be the publisher of record. For future books, buy directly from your national agency.

My ISBN shows the wrong title or format in book databases. Log in to your agency account and update the record. Data can take a while to update in retailer and library systems, so fix it early.

I can't find which ISBN I used for which book. Your agency account lists your assigned numbers. Keep a simple spreadsheet with ISBN, title, format, edition, and the stores where each one is used.

I published an ebook without an ISBN and now want one. Most ebook stores let you publish a new version with an ISBN, though some treat it as a new product. Check the store's help pages before you change anything, especially if the book already has reviews.

You don't need an ISBN to publish an ebook on the major stores, and KDP covers paperbacks for free if Amazon is your only print outlet. If you want print distribution through IngramSpark, or your own name as publisher, buy ISBNs from your national agency before you publish. Decide where your book is going first, and the ISBN choice follows from that.