ISBNs vs ASINs: What Authors Need to Know in 2025
If you’ve been around the blog before, or if you’re self-publishing in 2025, you’ve likely heard the terms ISBN and ASIN thrown around, and maybe even wondered whether you need both—or either. Understanding the difference is crucial, because it affects how your book is discovered, distributed, and even sold in bookstores or libraries. This guide breaks it down in plain language, with a Canadian lens, so you can make informed decisions about your book’s future.
What Is an ISBN?
An ISBN (International Standard Book Number) is a globally recognized code assigned to a specific edition of a book. It’s essentially your book’s official ID number, helping bookstores, libraries, distributors, and wholesalers track and catalogue your title. Each format—print paperback, hardcover, or eBook—requires its own ISBN.
In Canada, self-published authors have a major advantage: ISBNs are free through Library and Archives Canada (LAC). Free ISBNs allow Canadian self-publishers to retain professional control and distribute widely without added costs.
When You Must Use an ISBN
Print books intended for bookstores or libraries. Without an ISBN, retailers and libraries won’t stock your book.
Ebooks distributed beyond Amazon. If you plan to sell through Kobo, Apple Books, or other platforms, you’ll need an ISBN for each edition.
Multiple editions. Each new edition, such as a revised paperback or hardcover, requires its own ISBN.
Owning your ISBN ensures you control the metadata associated with your book, which helps readers, retailers, and libraries find your title.
What is an ASIN?
An ASIN (Amazon Standard Identification Number) is Amazon’s internal product ID. Every product sold on Amazon has one, including Kindle eBooks. ASINs are generated automatically when you upload a Kindle eBook to Amazon KDP. Unlike ISBNs, ASINs are Amazon-specific and do not exist outside the platform.
What an ASIN Cannot Do
It’s not recognized by bookstores or libraries.
You cannot use it to distribute outside Amazon.
Metadata linked to an ASIN is owned by Amazon, not the author.
ISBN vs ASIN: The Core Differences
Your book’s ISBN is recognized worldwide; it is free to the author through Library and Archives Canada, and it is required for print, and wide distribution eBooks. The author owns their ISBN.
An ASIN is recognized only by Amazon, and is mainly necessary for eBooks that are being distributed by Amazon; for distribution beyond the platform, it is ineffective. It is issued by Amazon and therefore, Amazon owns it (not the author).
When You Need One, the Other, or Both
Scenario A: Publishing Only on Amazon
If your book will remain Amazon-exclusive, your ASIN is sufficient for Kindle distribution. For paperback editions through KDP, an ISBN is optional—you can use a free KDP ISBN.
The trade-off is that Amazon will be listed as the publisher, and you won’t control the metadata if you decide later to go for a wider distribution.
Scenario B: Publishing Wide
If you intend to distribute your book on Kobo, Apple Books, Google Play, libraries, or brick-and-mortar stores, you must have ISBNs for each format. ASINs alone won’t get your book accepted outside Amazon.
Owning your ISBNs keeps your metadata under your control and maintains consistency across all platforms.
Scenario C: Illustrated or Specialty Books
Books with images—children’s books, art books, memoirs with illustrations—benefit greatly from ISBN ownership.
For these particular genres, distribution beyond Amazon is usually best, as they are especially great fits for libraries, galleries, or specialty retailers.
Should You Use the Free KDP ISBN or Claim Your Own?
KDP allows authors to use a free ISBN for paperbacks, which can be convenient for beginners. However, there are drawbacks, and they pertain mostly to your limited role as the author and owner.
Pros of KDP ISBN:
Free and simple to assign
Works seamlessly with Amazon print distribution
Cons of KDP ISBN:
Amazon is listed as the publisher
Metadata is not transferable outside Amazon
Limits future distribution flexibility
Pro-Tip: Serious self-publishers often claim their own ISBNs to retain full control over metadata and publishing rights. With the ease and convenience offered by the Libraries and Archives Canada, it’s the most prudent course of action for Canadian self-published authors, who are publishing with the intention of selling their book to the widest possible audience.
2025 Update: What’s New in ISBN/ASIN Guidance
Even though the basic principles remain the same, some updates for 2025 include:
Emphasis on author-owned ISBNs: Libraries, distributors, and metadata aggregators increasingly expect authors to own their ISBNs.
Better metadata control: Accurate ISBN metadata improves discoverability and search results across platforms, granting your book greater visibility.
Wider library adoption: Libraries rely on ISBNs to catalogue both eBooks and physical books in their required orderly fashions.
Frequently Asked Questions
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An ISBN is a globally recognized book identifier used by bookstores, libraries, and distributors. An ASIN is Amazon’s internal product ID for Kindle and other Amazon items. ISBNs are required for wide distribution; ASINs are Amazon-specific.
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Not necessarily. If your eBook will only be sold on Amazon, the ASIN is sufficient. However, if you plan to distribute your eBook on other platforms like Kobo or Apple Books, you’ll need an ISBN.
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Yes, KDP offers free ISBNs for paperbacks. Keep in mind that Amazon will be listed as the publisher, and metadata control is limited. Owning your own ISBN gives you more flexibility and professional control.
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Each edition and format of your book requires its own ISBN. For example, your print paperback, hardcover, and eBook versions each need a separate ISBN.
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Canadian authors can claim free ISBNs through Library and Archives Canada (LAC). The process is straightforward and allows full control over your book’s metadata.
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Yes. Use the ASIN for your Amazon Kindle eBook and an ISBN for print editions and distribution outside Amazon. This approach maximizes discoverability, professional credibility, and long-term flexibility.
Conclusion and Recommendation
With this knowledge, you can confidently plan your publishing strategy and ensure your book reaches as many readers as possible, both in Canada and internationally. In our view, especially for Canadian self-published authors, claiming your free ISBN through LAC has never been more beneficial. It is the most comprehensive course of action; it’s free to authors and it falls under their ownership. As a Canadian company, enjoying the advantage of all the ISBN has to offer is a no-brainer!
Applying for and registering ISBN’s for our authors is something we do everyday, and it’s our main recommendation for anyone self-publishing their book. Our team of self-publishing experts guides authors through ISBN selection and registration on their behalf.
Contact us today to learn how we can help you along your self-publishing journey. Our goal as experts is to remove the guesswork so authors can focus on their craft, writing, and know their book is professionally prepared for wide distribution, marketing, and beyond.
