Do You Need an ISBN for an Ebook on KDP?
On KDP, an ebook does not need an ISBN, but a paperback usually does. Here is what KDP's help pages say about each, the two ISBN options, and what a free ISBN does to your publisher name.
By Shri and Sarath · 5 min read · Updated 20 October 2026 · Facts checked 20 October 2026
Every KDP fact below comes from KDP's own help pages, read on 2026-10-20. This guide covers KDP only. Other stores set their own identifier rules, so check each one's pages. KDP changes its rules, so confirm on the linked pages before you publish.
Ebooks: no ISBN needed on KDP
KDP's Get an ISBN page says plainly: "You don't need an ISBN for eBooks on KDP." Its page on what an ISBN is says "eBooks and low-content books are the only formats where an ISBN is optional." The metadata guidelines agree: "you do not need an ISBN to publish an eBook, but you need an ISBN to publish a paperback or hardcover (except for low-content books)."
KDP also says free ISBNs "are only available for paperback and hardcover books." So for an ebook the choice is not between a free ISBN and your own: KDP simply doesn't assign one. KDP's ISBN pages that we read don't mention the ASIN, Amazon's own product identifier, and they don't say what identifies an ebook on the Amazon site. Don't assume details KDP's pages don't give.
If you do buy an ISBN for an ebook, KDP's pages we read say nothing for or against it. The same applies when the ebook is sold somewhere other than KDP: the identifier rules there belong to that store.
Paperbacks and hardcovers: the two options
KDP says an ISBN is "a unique identifier for books" that helps bookstores, libraries, distributors and readers find and reference your book. Each format of your book, paperback versus hardcover, needs its own ISBN, and the same ISBN cannot be reused across formats or across new editions that change significantly from the original.
Cost
- Free KDP ISBN
- Free
- Your own ISBN
- You cover the cost of the ISBN
Where you can publish
- Free KDP ISBN
- Only with KDP
- Your own ISBN
- Outside KDP too
Imprint (publisher name)
- Free KDP ISBN
- "Independently published"
- Your own ISBN
- The imprint you register and enter
Requirements
- Free KDP ISBN
- None from you, KDP registers it
- Your own ISBN
- Details in KDP must match the ISBN agency's record exactly
Formats
- Free KDP ISBN
- Paperback and hardcover
- Your own ISBN
- Paperback and hardcover (ebooks don't need one)
KDP says a free ISBN is registered with Bowker, the US ISBN agency, using your book details. Free ISBNs can only be used on KDP and cannot be used to publish outside KDP. To get one, open the book's content page on your Bookshelf, find the ISBN section, choose Get free KDP ISBN, then Assign ISBN.
Imprint: the part people overlook
KDP defines an imprint as "the name of the publisher associated with your book's ISBN." With your own ISBN you can list your own publishing imprint, such as a business or brand name. With a free KDP ISBN, the imprint shows as "Independently published." That is a trade: the free ISBN costs nothing but you cannot brand it.
With your own ISBN, KDP checks that your imprint matches what is on file with the ISBN agency, and if there is a mismatch you won't be able to publish. KDP says entries are case-sensitive, that even extra spaces at the end of the imprint can cause a mismatch, that you must not enter placeholders such as "unknown" or "n/a," and that the field is limited to 100 characters. It recommends copying and pasting directly from the agency's record. The title and author name you enter must match the ones you registered the ISBN with too.
ISBN agencies differ by country. KDP's pages name Bowker as the US agency, and speak of Bowker "or local ISBN agency" for other places. KDP's pages say Bowker offers discounted rates for KDP authors, but we don't quote any price here because prices are the agency's to state and change. Check your country's agency for its current terms.
Low-content books and an ISBN
For low-content books such as notebooks and planners, KDP says an ISBN is optional, and low-content books are not eligible for the free KDP ISBN. You can use your own ISBN or publish without one. Our guide to KDP's low-content book rules covers what else changes without an ISBN.
Changing an ISBN, fixing errors and barcodes
KDP's page on changing an ISBN says: "ISBNs cannot be changed if your book is published." To update the ISBN, or details such as the title or author name, you have to unpublish the book and publish a new edition, created the way you made the first one. An ISBN can be updated while the book is still in draft, from the ISBN section of the content page. If you change your own ISBN's details with the agency, KDP says it takes 5 business days to register the change, and you should wait before updating the book on KDP.
If KDP shows "Please fix the highlighted issue" with nothing highlighted, KDP says that typically means a problem with your ISBN or imprint. It names two causes: a spelling, spacing or punctuation mistake, or a title, author name or imprint that doesn't match the agency's record. The fix it gives is to check the agency's website and copy from it. KDP adds that for questions about ISBN metadata you need to contact the agency, in its example Bowker.
Barcodes are separate from the ISBN itself. KDP's barcode page says you can upload a cover with or without a barcode, and that if you use Cover Creator or provide none, KDP places one on the back cover. If you provide your own and it includes an ISBN, the ISBN must be valid and match your book's ISBN exactly. KDP says a cover with images or text in the barcode location will be rejected. KDP recommends an Amazon-placed barcode when yours fails validation. KDP's barcode page doesn't say what an ebook cover needs, since an ebook has no printed barcode.
ISBN checklist
- Ebook only: you can publish on KDP without an ISBN.
- Paperback or hardcover: decide between the free KDP ISBN and your own before you upload.
- Want your own publisher name shown? That needs your own ISBN.
- Plan to sell the paperback outside KDP? A free KDP ISBN can't be used there.
- With your own ISBN, copy the title, author and imprint from the agency's record, spaces and capitals included.
- Use a separate ISBN for each format, and for a significantly changed edition.
- Low-content book: the free ISBN isn't available, so pick your own ISBN or none.
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