No. You do not need an ISBN to sell a book from your own website, whether that is an ebook or a printed copy you send out yourself. The reason is that an ISBN is used by the book trade to order and catalogue titles, and nobody in that trade is handling a direct sale from your own site.
Do You Need an ISBN to Sell a Book Yourself?
An ISBN is not required for a book you sell yourself, and the US ISBN Agency says so on its own FAQ page. It asks what happens when a publisher (which, if you self-publish, means you) is “selling their books on their own and are not trying to place them in stores or libraries or with wholesalers”. Its answer is flat: “No, an ISBN is not required.”
An ISBN, or International Standard Book Number, identifies one edition of one title from one publisher, in one format. A paperback and a hardcover are two formats, and so are an EPUB and a PDF. The number exists so that shops, wholesalers and libraries can order and shelve the right thing. A book you sell only from your own site never enters that ordering system, so the number has no work to do.
But be careful how far you take that. Bowker notes that ISBN use “is prescribed by law in some countries”, without naming them. So check the rules where you publish.
Why Might Your Printer Ask for an ISBN Anyway?
Some printers ask for an ISBN even when you are not selling through shops, and the reason is that the requirement follows the distribution channel rather than the book itself. IngramSpark draws that line in its own FAQ: “If you intend to distribute your book, you’ll need an ISBN for each format of your book. If you don’t intend to distribute your book, we can assign a SKU to your book for printing purposes only.”
Distributing here means offering the book for sale through shops, wholesalers and online retailers. Selling copies yourself is not distributing, however many you sell. The SKU is a free reference number that lets IngramSpark print the book without listing it for sale anywhere. Short-run and local printers usually want nothing but your files.
Amazon KDP works differently, because you cannot order copies to sell without publishing the book there first. For a paperback or hardcover, that step does require an ISBN: KDP states that “eBooks and low-content books are the only formats where an ISBN is optional”, low-content meaning notebooks, journals and the like. Once the book is published you can order author copies at print cost, and KDP is explicit that “you are welcome to resell or give away author copies you ordered from KDP”.
One thing to watch if a platform offers you a free ISBN while you are setting the book up: it belongs to them, not to you. We compared the trade-offs in our post on free ISBNs and what they cost you in portability.
If your book only ever sells from your own website or your own table at an event, you can publish it without an ISBN and nothing will stop you selling it. Buy one when a specific door needs opening: a distributor, a bookshop, or anywhere else that catalogues what it stocks. You can assign a number to the book when that day comes.
Frequently Asked Questions
Is there such a thing as an eISBN?
No. An ebook takes an ordinary ISBN, and the standard has no separate category for ebooks, whatever some retailer sites call it. What is true is that an ebook is a different format from the paperback, so it needs its own number rather than sharing the print one.
Do you need a separate ISBN for each format of the same book?
Yes, if you assign ISBNs at all. Each format is its own product, so a paperback, a hardcover, an EPUB and a PDF are four products and four ISBNs. Authors who sell an EPUB and a PDF together as a single download often expect the two files to share one number, and they cannot.
Do you need an ISBN to sell books at an event or a signing?
No. Selling copies by hand at a fair, a signing or a market stall is the same situation as selling from your own website: no shop, wholesaler or library is ordering the book, so nothing requires a number. Copies from a print-on-demand platform may carry one already, though, and that depends on the platform. IngramSpark can print without one; Amazon KDP requires an ISBN for a paperback or hardcover.
Can you add an ISBN later, or if you start selling through a retailer?
Yes. Nothing about assigning an ISBN depends on doing it before the first sale, and copies you have already sold can stay as they are. Adding one to a finished book is a routine update rather than a rebuild: in an ebook it means the copyright page and the file’s metadata, and in print it also means the barcode on the back cover, so the cover file is updated too. Whether you need one at all depends on where you publish next. Amazon KDP treats it as optional for ebooks and issues an ASIN instead, while a distributor selling into shops will require one.
Does an ISBN give you any copyright protection?
No. An ISBN is an inventory and cataloguing number, and it creates no rights of any kind. The US ISBN Agency states this explicitly, as does Library and Archives Canada. Your copyright exists from the moment you write the book, and registering it, where that applies in your country, is a separate process.
Can you reuse an ISBN from a book you have stopped selling?
No. Once an ISBN has been assigned to a title it can never be reused, even if the book is out of print and no longer for sale anywhere. Numbers you have bought but never assigned to anything are still available to use, because ISBNs themselves do not expire.
