Basic VS Custom ISBN Number: Which should you prefer?

You’ve poured your heart, soul, and countless late nights into writing your book. The manuscript is edited, the cover design is perfect, and you’re standing at the final hurdle before hitting “publish.” And then you run into a seemingly small but surprisingly complicated question: the ISBN Number.

You see options for a “free” or “basic” ISBN from your publishing platform (like Amazon KDP or IngramSpark), and you see an option to buy your own. What’s the difference? And more importantly, does it really matter?

The short answer is: Yes, it matters. A lot.

Choosing between a basic, platform-provided ISBN and a Custom ISBN Number you purchase yourself is one of the most critical business decisions you’ll make as an independent author. It directly impacts your professionalism, your distribution options, and your long-term control over your own book.

Let’s dive deep into the world of ISBNs so you can make the right choice for your author career.

What is an ISBN Number?

Before we compare “basic” and “custom,” let’s get on the same page.

An ISBN Number (which is technically redundant, since ISBN stands for International Standard Book Number, but it’s how we all say it!) is a 13-digit code that acts as a unique identifier for your book. Think of it as your book’s Social Security Number or its fingerprint.

No two books in the same format have the same ISBN. It’s the global standard used by publishers, booksellers, libraries, and distributors to:

• Identify a specific book (title, author, publisher).
• Identify its specific format (paperback, hardcover, ebook, audiobook).
• Track inventory.
• Process orders.
• Report sales.

If you want your book to be sold in any capacity beyond just a personal blog download, you need an ISBN. The real question is, who should be the source of that number?

The “Basic” ISBN: The Free and Easy Option

A “basic” ISBN is the number offered to you, often for free, by a self-publishing or print-on-demand (POD) platform. Amazon KDP, IngramSpark, Barnes & Noble Press, and Lulu all offer one.

When you’re uploading your book, you’ll see a checkbox that says something like, “Assign me a free KDP ISBN.” It feels like a no-brainer. It’s free, it’s one less step, and you can get on with publishing.

The Pros

• It’s Free: This is the number one (and pretty much only) reason authors choose it. It costs you nothing.
• It’s Simple: You just click a button. You don’t have to go to another website, fill out forms, or manage any metadata. It’s automatic.

The Cons

This is where things get serious. That “free” ISBN comes with some very heavy strings attached.

1. The Publisher of Record: This is the most important concept to understand. Whoever provides the ISBN is listed as the “Publisher of Record” in the book’s official metadata.
   • If you use the free KDP ISBN, the publisher listed for your book will be “Independently published” (or formerly “CreateSpace Independent Publishing Platform”).
   • It will not be your name. It will not be your publishing company’s name.
   • This immediately signals to any bookseller, librarian, or industry professional that it’s a self-published KDP book. While self-publishing is widely respected, this can still carry a stigma and may make some brick-and-mortar stores less likely to stock your title.
2. It is NOT Portable: This is the second-most important catch. A platform-provided ISBN is locked to that platform for its entire life.
   • Let’s say you take the free KDP ISBN for your paperback. You can only sell that paperback on Amazon.
   • If you later decide you want to sell it on Barnes & Noble, or make it available for libraries through IngramSpark, you cannot use that KDP-provided ISBN.
   • You would have to get another free ISBN from IngramSpark. Now, you have two different versions of your book floating around the internet with two different ISBNs, which splits your sales data and looks confusing and unprofessional.
3. You Can’t Take it to a Local Printer: Want to do an offset print run of 1,000 copies with a local printer to sell at events? You can’t. That free ISBN is tied to KDP’s system, not to your book. You’d have to get another ISBN (or publish a version without one, which you can’t sell in stores).

In short, a “basic” ISBN is like renting a post office box. It works, but it’s not your permanent address, you can’t take it with you when you move, and everyone knows it’s just a box at the post office, not your actual home.

The “Custom” ISBN: The Professional Choice

A Custom ISBN Number (or author-purchased ISBN) is one that you buy yourself, directly from the official ISBN agency in your country.

• In the United States: This is ISBNServices.
• In the United Kingdom: This is Nielsen.
• In Australia: This is Thorpe-Bowker.
• In Canada: This is Library and Archives Canada (where they are, fortunately, free!).

When you buy your own ISBN, you are buying the right to be the publisher.

The Pros

1. YOU are the Publisher: This is the game-changer. When you buy a Custom ISBN Number, you get to fill out the metadata. In the “Publisher” field, you can put your own name (“Jane Doe”) or, even better, the name of your publishing company (“Scribe Publications,” “Dragonfly Press,” or whatever you want to call your author business).
   • This gives you instant professionalism. A bookstore looking up your book sees a legitimate publisher name, not “Independently published.”
2. It is 100% Portable: This is the power of ownership. Your Custom ISBN Number is tied to your book’s specific format (e.g., the paperback edition), not to a printer or a seller.
   • You can assign your custom ISBN to your paperback and upload it to KDP.
   • You can then take that exact same file and that exact same ISBN and upload it to IngramSpark (to get wider distribution to other stores and libraries).
   • You can then take that exact same file and ISBN to a local offset printer and print 5,000 copies.
   • It doesn’t matter where it’s printed or sold. The ISBN is yours, and it follows the book everywhere. This consolidates all your sales and listings under one, professional identity.
3. Total Control: You control all the metadata. The title, subtitle, author name, description, categories, and publisher name are all set by you in your ISBN agency’s portal (e.g., Bowker). This becomes the “master record” for your book across the entire global supply chain.
4. Enables True “Wide” Distribution: If your goal is to be in physical bookstores, you must be on a distributor like IngramSpark. While IngramSpark offers a free ISBN, it has the same limitations as KDP’s (it locks you to their platform). The only way to be on both KDP (for Amazon’s prime printing) and IngramSpark (for wide distribution) with the same book edition is to use your own Custom ISBN Number.

The Cons

• Cost: This is the main barrier. A Custom ISBN Number is an investment. In the US, Bowker charges $125 for a single ISBN. This is steep.
• The Smart Solution: Bowker (and other agencies) knows publishers need more than one. They sell ISBNs in bulk. In the US, a 10-pack costs $295. This drops the per-ISBN price from $125 to just $29.50. A 100-pack is $575, making them $5.75 each.
• Minor Admin Work: You have to create an account, buy the numbers, and then manually “assign” one to your book by filling out a form with your title, author name, trim size, etc. It’s an extra 15-minute step in the publishing process.

How to Choose: A Guide for Your Author Goals

So, which path is right for you? It all comes down to your goals. You should choose a BASIC (Free) ISBN if…

• You are a pure hobbyist, and this book is just for family and friends.
• You have zero budget and are just experimenting with publishing for the first time.
• You only plan to sell your book on Amazon, and you have no desire to ever see it in a physical bookstore or library.
• You genuinely do not care about being listed as the publisher or having a professional imprint.

You MUST choose a CUSTOM (Purchased) ISBN if…

• You are serious about your author career, even if it’s “just” a side-business.
• You want your book to be available in physical bookstores or libraries (this requires IngramSpark, which necessitates a custom ISBN to also be on KDP).
• You want your own publishing company name (an “imprint”) listed as the publisher.
• You want the flexibility to print your book anywhere, anytime, with any printer (including offset printers for large runs).
• You are publishing multiple formats (e.g., a paperback and a hardcover). Each one will need its own ISBN, and buying a 10-pack is the only sane, cost-effective way to do this.

The Verdict: An Investment in Your Own Brand

Think of it this way: Using a free ISBN is like building a house on land you don’t own. It’s cheap and fast, but the landlord (the platform) can change the rules, and you can’t move your house.

Buying a Custom ISBN Number is like buying the plot of land before you build. It costs money upfront, but you own it. You control it. You can build whatever you want on it, and it’s yours forever.

For the vast majority of authors who want to be taken seriously and retain full control over their work, the choice is clear. Biting the bullet and buying a 10-pack of ISBNs from your country’s official agency is the first and most important investment you can make in your professional author business.

Frequently Asked Questions (FAQs)

Q: Do I need an ISBN number for my ebook?

A: It depends. Amazon Kindle does not require an ISBN for ebooks; they will assign their own internal identifier called an ASIN (Amazon Standard Identification Number). However, if you want to sell your ebook on other platforms (Apple Books, Kobo, Barnes & Noble Nook, etc.), you will need an ISBN for your ebook. This must be a different ISBN from your paperback.

Q: Does each format need its own ISBN?

A: Yes. This is a critical rule. Your paperback, hardcover, audiobook, and ebook must each have their own unique ISBN Number. This is why buying a 10-pack is so cost-effective.

Q: I see websites selling single ISBNs for $50. Are those legit?

A: NO. Be very careful. The only legitimate source for an ISBN Number is the single, official agency for your country (like Bowker in the US). Companies that buy ISBNs in bulk (e.g., a block of 1000) and then “resell” them to authors one at a time are a dangerous gray market. When you buy from them, they (the reseller) are listed as the Publisher of Record, not you! You’re paying money to end up in the exact same bad situation as using a free platform ISBN. Only buy direct from your country’s official agency.

Q: What if I use a free KDP ISBN now and want to change later?

A: You can’t. An ISBN is permanently assigned to an edition. If you publish with a free KDP ISBN and later decide you want to “go wide” with your own Custom ISBN Number, you would have to:

1. Unpublish the original KDP book.
2. Publish an entirely new book with your new custom ISBN. This new book will be a separate product on Amazon. It will not have any of the sales rank or reviews from your old version. You lose all your history. It is much better to start with your own ISBN from day one.

Q: Do my ISBNs expire if I buy a 10-pack?

A: No. When you buy a block of ISBNs from an agency like Bowker, they are yours forever. You can use one today, one next year, and one a decade from now. They are an asset you own until you assign them to a book.