How to Get an ISBN as a Self-Published Author, and What It Will Not Do

An ISBN costs between nothing and $125 depending on where you get it, and the cheap route can quietly decide who is listed as your book's publisher for the life of that edition. Most self-published authors pick a route in the KDP setup screen without knowing the trade they are making. This guide covers what the number does, where it comes from, what the free options cost you, and what to do with it once you have one.

What an ISBN identifies

An ISBN is a 13-digit product identifier for a specific edition of a book in a specific format from a specific publisher. Since January 1, 2007 every new ISBN has 13 digits, split into five elements: a prefix (978 or 979), a registration group for the country or language area, a registrant element for the publisher, a publication element for the individual title, and a check digit. If you still have a 10-digit number from an older book, our post on ISBN-10 versus ISBN-13 explains how the two relate and how to convert.

The rule that trips people up is one number per format. The ISBN Users' Manual from the International ISBN Agency requires a separate ISBN for each product form, so a paperback, a hardcover, an EPUB and an audiobook of the same book are four ISBNs. A new edition with significant changes to the text, or a change of title, also needs a new number. A reprint with corrected typos, a new cover, or a new price does not. Bowker's own guidance is that most books end up using two or three.

Two things the number does not do. It is not copyright. The International ISBN Agency states that an ISBN conveys no legal or copyright protection, and in the United States your copyright exists from the moment you write the work whether or not you register it. And it is not a barcode. The barcode on a back cover is an EAN-13 symbol that encodes the ISBN, usually with a five-digit price add-on in the US and Canada. You need the number first and generate the barcode from it, which any barcode generator can do.

Where ISBNs come from

Each country has one official agency. In the United States that is Bowker, which sells through myidentifiers.com. In the UK and Ireland it is Nielsen. In Canada it is Library and Archives Canada, which issues ISBNs free to publishers located in Canada. The International ISBN Agency keeps a directory of every agency, and the one you use is decided by where you as the publisher are located, not where you plan to sell.

Bowker's prices as listed on September 15, 2026:

ISBNs never expire, so if you expect to publish more than one book, or one book in three formats, the block of 10 is the sensible purchase. Buying from Bowker registers you as the publisher of record, and you choose the imprint name that appears on the record. That name is what retailers show as the publisher.

Nielsen's store lists a single ISBN at £93 and a block of 10 at £174, including VAT, as of the same date.

The third route is a service that assigns the number and handles the registration for you. ISBNdirect is one: $19 per ISBN, issued through Bowker, with the number in your dashboard within minutes of checkout. The portal walks you through the Bowker metadata fields and submits the record to Books in Print and Bookwire, and it includes the barcode files and a landing page for the book. The number works on KDP, Lulu, Draft2Digital, PublishDrive and Barnes & Noble Press. The trade is that the publisher name on the record is ISBNdirect's, "Staten House", rather than your own imprint. Royalties and copyright stay with you. If your own imprint name on the record matters for this book, buy from Bowker directly. If it does not, this route gets a portable, fully registered number for a sixth of Bowker's single price.

The free KDP and IngramSpark ISBNs

Amazon KDP assigns a free ISBN to any paperback or hardcover. IngramSpark does the same for self-publishers located in the United States. Both are real ISBNs, and for a book that will only ever be sold on that one platform, either is fine.

The trade-off is in two parts. First, the platform becomes the imprint of record. KDP's free ISBN lists the publisher as "Independently published." IngramSpark's lists it as "Indy Pub." That is what shows on the product page, in library catalogues and in wholesale data. Second, the number is locked to the platform. KDP's help pages say its free ISBNs "can only be used on KDP." IngramSpark says its free ISBN can only be associated with your title on IngramSpark, cannot be transferred to another account, and that switching to your own ISBN later means setting the book up as a new title. Neither platform accepts the other's free ISBN.

So the same paperback published on both KDP and IngramSpark with free numbers ends up as two different products with two different publishers of record. If you want one edition listed once, under your own name, everywhere, buy the ISBN and enter it on both platforms with identical title, author and imprint details. KDP checks your imprint against the Bowker record, the check is case-sensitive, and a mismatch, even a trailing space, blocks publishing.

Ebooks are a separate case. KDP does not require an ISBN for a Kindle ebook and assigns an ASIN instead. You can give an ebook one of your own ISBNs, and some retailers and library platforms use it to match editions, but there is no free KDP ISBN for ebooks and nothing forces you to buy one.

978 and 979

Since 2020 Bowker has been issuing ISBNs that start with 979-8, a prefix unique to the United States, because its supply of 978 numbers in some block sizes ran low. A 979 ISBN is not a lesser number. It works everywhere a 978 number does. The one practical difference is that a 979 number has no ISBN-10 equivalent, so never let a form or a tool convert it to ten digits. Any retailer still asking for an ISBN-10 needs the 13-digit number and nothing else.

What to put in the metadata

An ISBN on its own is a blank record. Its value comes from the data attached to it, and you attach that data in three places.

At the agency, log into your Bowker account, or the portal of whichever agency or service issued the number, and assign the ISBN to the title. Enter the exact title and subtitle, the author name as it appears on the cover, the imprint, the format, the page count, the publication date and the price. This feeds Books in Print, the database retailers and libraries query.

At the retailer or printer, enter the same details, character for character. The publisher name and title must match what the agency holds.

In the book, print the ISBN on the copyright page (the verso of the title page) preceded by the letters ISBN, and put the barcode in the lower right of the back cover near the spine. If the ISBN is the only identifier on your copyright page, that is normal. A Library of Congress Control Number is a different thing with a narrower purpose, and our post on what an LCCN is covers why most self-published authors can skip it.

Next steps

Count the formats you plan to release, then decide whether the publisher name on the record matters for this book. If it does not and the book lives only on Amazon, take KDP's free number. If you will print or sell anywhere else, or you want your own imprint listed, buy a block from Bowker or a single registered number from a service before you upload anything, because a book published under a free ISBN has to be re-listed as a new title to switch. Assign the number at the agency with complete metadata the same day you get it, and use that exact data on every platform afterwards.