ISBN Numbers and Self-Publishing: What You Need to Know
- Phil Carlucci
- Dec 15, 2025
- 3 min read
Updated: Feb 25
This post is part of our Self-Publishing Series, designed to provide important information for writers considering the editorial responsibilities, benefits and costs associated with publishing their own work. For details on available editing services or to learn more about getting your writing into print, contact PJC Editing for a free editorial consultation.
ALSO IN THE SELF-PUBLISHING SERIES
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ISBN numbers are among the grittier details of the self-publishing process.
Copy editing, formatting, cover design...these are all fairly self-explanatory and better understood by writers, whether they are looking to publish their first book or their fifth. But ISBN numbers and barcodes are harder to grasp.
Here are some basics to know about the ISBN:
ISBN stands for International Standard Book Number, and it is essentially a serial number for your book. You will see it printed on the barcode of a book and on the copyright page. If searching for books on sites like Amazon, you'll see it listed with the product details.
Every edition of your book needs its own ISBN. If you want to publish a paperback and a hardcover, you need two separate ISBNs.
An ISBN cannot be reused. Once you've assigned it to a particular edition, it can't be used later on a different or updated edition.
Bowker is the official distributor of ISBN numbers in the United States. Authors can purchase individual numbers or blocks of numbers (for multiple and/or future editions) there. Buying ISBN numbers from Bowker means you, the writer, are the owner and publisher of the assigned work.
ISBNs are also available for free through self-publishing services like Amazon KDP and IngramSpark. By using their free ISBNs, you are acknowledging that those services are the publisher — not you. Depending on the service, there may be restrictions on where you can sell assigned editions.
What to do with this information:
If your self-publishing plan is to write a book, give copies to friends and family, and sell it directly through a personal website or at fairs and markets, then you don't necessarily need an ISBN.
But if you intend to list your book on Amazon and have it available in digital databases so bookstores and other retailers can purchase it, then you need to have an ISBN for every edition you plan to sell to consumers.
Consider purchasing your ISBNs before you get to the tail end of the writing and editing process. It's not urgent, but it should give you peace of mind knowing you have basic details in hand as you finish your book. Plus, you can't initiate listing your book anywhere without having the ISBN, so there's no downside to getting it done.
You can use the free ISBNs supplied by Amazon, Ingram and other services, but keep in mind there will be restrictions that could potentially make it less beneficial to your self-publishing goals.
For instance, with Amazon KDP, you will only be able to publish the assigned edition on the KDP platform. See this Amazon info page for specifics on the pros and cons of using a free or purchased ISBN on the KDP platform.
What about barcodes?
The barcode is essentially your ISBN and book info written in computer code. It allows bookstores and distributors to scan your book and retrieve all the necessary data from the ISBN database. Owning an ISBN does not magically create a barcode, however. You need to create one by inputting your purchased ISBN number and your book price, and that can be done easily on sites like Kindlepreneur.
Once you have that barcode, you or your cover designer can easily print it on your book.
If using a free ISBN from one of the publishing platforms, a barcode will be provided, and you will not need to do any generating, printing or designing.
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