Free KDP ISBN vs your own ISBN: what changes and which to choose

The choice can’t be undone once the book is out: it decides the publisher name on your product page and where else this edition can be sold. Below: the two options side by side, which formats need a number, what your own costs, barcodes, and how to choose.

How do the free and your own ISBN compare?

An ISBN is a 13-digit number, usually starting with 978 or 979, that identifies one format and edition of a book. KDP gives you two ways to get one for a print book:

Which formats need an ISBN?

KDP’s rule is one ISBN per format and per new edition. The same number can’t be reused across formats, or for a new edition with significant changes.

The low-content exception applies to books with minimal, repetitive interiors meant to be filled in, such as notebooks, planners and logbooks (in kdpbook, the planner & logbook, lined notebook, sketchbook and password book types). Published without an ISBN, a low-content book is identified by its ASIN and gets no Look Inside sample; Expanded Distribution isn’t available to low-content books with or without an ISBN. Coloring, puzzle and children’s books are not low-content, so they need an ISBN like any other book. The low-content guide explains the difference.

Which imprint shows on your product page?

The imprint is the publisher name tied to the ISBN, and Amazon shows it on the product page. With the free KDP ISBN it is always “Independently published”. With your own ISBN, it is whatever you registered with the agency: your name, a press name or a brand.

With your own ISBN, KDP checks your entry against the agency’s record, and a mismatch blocks publishing:

• Register the ISBN with the right title, author name, format and imprint before you enter it in KDP. The fields are case-sensitive, and a spelling, spacing or punctuation difference is enough for a mismatch, so copy and paste from the agency’s site.
• The imprint field in KDP takes up to 100 characters.
• After you update the record at the agency (Bowker in the US), KDP can take up to 5 business days to pick up the change before you can save the book.

Can you sell the same edition outside Amazon?

KDP is explicit that its free ISBNs can only be used on KDP. That doesn’t keep a KDP paperback off other stores: Expanded Distribution, KDP’s own channel to other retailers and libraries, works with either ISBN and pays 40% of the list price minus printing cost. It is paperback only and excludes low-content books, coloring books and journals, among others.

What the free ISBN rules out is publishing the same edition through another service. For that you need your own ISBN, and KDP adds a condition for Expanded Distribution: your book’s ISBN must not have been submitted for distribution through another service. In practice, choose one route per ISBN: KDP with Expanded Distribution, or KDP for Amazon plus another distributor for everywhere else.

What does your own ISBN cost?

ISBNs come from national ISBN agencies. In the US the official agency is Bowker (myidentifiers.com), which warns that an ISBN obtained from another source might not identify the publisher accurately. Its prices on September 28, 2026:

ISBNs never expire, so leftovers keep. Because each format needs its own number, the cost adds up faster than the number of books. From 3 ISBNs, the 10-pack costs less than buying singles:

• KDP discount. KDP’s help page links to a discounted Bowker rate for KDP authors. The discounted price isn’t stated on KDP’s page, so check it on Bowker’s site before you buy.
• Canada. ISBN Canada (Library and Archives Canada) gives free ISBNs to eligible publishers. It currently says new accounts can take up to two months to process, so apply before you need the number.
• Elsewhere. The International ISBN Agency lists the official agency for each country. Prices and eligibility vary by agency.

Do you need to buy a barcode?

You don’t need to buy a barcode for a KDP print book. If your cover PDF doesn’t include one, KDP adds a barcode for free in a 2 × 1.2 in area in the lower right of the back cover, so keep that area clear. Bowker sells an ISBN with a barcode for $150, $25 more than the ISBN alone.

If you add your own barcode, KDP asks for 100% black on a solid white background, at least 1.4 × 0.8 in, and an ISBN that matches the book exactly. The cover size calculator marks the barcode area on its template.

Can you switch ISBNs later?

KDP says ISBNs cannot be changed once a book is published. To move from the free ISBN to your own (or the other way), you unpublish the book and publish a new edition, created like the first one. The imprint and the trim size are locked the same way, and so is the ink; only black-and-white books can switch paper type after publishing (see trim sizes and paper types). While the book is a draft, you can still change the ISBN in its Paperback or Hardcover Content page.

A new edition is a new book in KDP: it needs its own ISBN, and it counts toward KDP’s weekly limits of 2 new titles created and 2 submitted per format. Decide on the ISBN before the first publish, for every format you plan.

Which one should you pick?

• Free KDP ISBN: your book will be printed and sold through KDP only (Amazon plus, for paperbacks, Expanded Distribution), you’re fine with “Independently published”, or you’re testing a first book or a new niche.
• Your own ISBN: you want your imprint on the product page, you plan to publish the same edition through another service, you publish many books and formats (at pack prices), or you want Look Inside on a low-content book.
• No ISBN: Kindle eBooks, and low-content books where you accept no Look Inside and no Expanded Distribution.

Hardcovers start at 75 pages and always need their own ISBN; the paperback vs hardcover guide covers the rest of that choice. kdpbook.io doesn’t sell or assign ISBNs: you pick one in KDP when you set up each print format, and the listing sheet of every book says whether it is low-content, which decides whether the free KDP ISBN is offered.