How to Get an ISBN for Your Book

📖 Quick reference: For a shorter overview, see our ISBN glossary entry.

If you're a self-published author getting ready to publish your first book, you've probably run into one of the most confusing topics in the industry: ISBNs.

Should you buy one? Where do you get one? Do you even need one? Why does one company charge $125 for a single number? And what about the free ISBNs that Books.by offers — are those legit?

ISBNs are the #1 source of confusion for new self-published authors. The information out there is fragmented, often outdated, and frequently biased toward selling you ISBNs you may not need. This guide cuts through all of that.

We'll explain exactly what an ISBN is, whether you need one, how to get one in the US (via Bowker/MyIdentifiers) and internationally (including Thorpe-Bowker in Australia), and how to avoid overpaying. By the end, you'll know exactly what to do.

What Is an ISBN?

ISBN stands for International Standard Book Number — a unique 13-digit identifier assigned to every edition of every book published worldwide. Think of it as a social security number for your book. No two books share the same ISBN, and each ISBN points to one specific edition of one specific title.

The ISBN system is managed by the International ISBN Agency, headquartered in London. Each country has its own designated ISBN agency. In the United States, that agency is Bowker. In Australia, it's Thorpe-Bowker. In Canada, ISBNs are free through Library and Archives Canada. The price differences between countries are staggering.

The Structure of an ISBN

Every ISBN-13 is made up of five parts. Here's what each segment means:

• Prefix element (978 or 979): Identifies the number as part of the ISBN system. Currently, 978 is most common; 979 is being phased in as 978 numbers are exhausted.
• Registration group (country/region): Identifies the country, geographical region, or language area. For example, 0 and 1 = English-speaking countries, 2 = French-speaking, 3 = German-speaking.
• Registrant element (publisher): Identifies the specific publisher. Larger publishers get shorter registrant numbers, allowing more title numbers.
• Publication element (title): Identifies the specific edition and format of the title.
• Check digit: A single digit calculated from the other 12, used to verify the ISBN is valid.

ISBN-10 vs ISBN-13

You may occasionally see references to ISBN-10 (a 10-digit format). ISBN-10 was the standard until January 1, 2007, when the international community switched to ISBN-13 to expand the available number pool. All ISBNs issued today are 13 digits. If you have an old ISBN-10, it can be converted to ISBN-13 by adding the 978 prefix and recalculating the check digit — but you almost certainly won't need to worry about this.

ISBN vs Barcode

Do You Actually Need an ISBN?

This is the question most authors are really asking. It depends on what you're publishing and where you're selling it.

For Print Books: Yes, Effectively Required

If you're publishing a physical book — paperback or hardcover — you need an ISBN. Period. Bookstores won't stock it, libraries won't catalog it, and distributors won't carry it without one. Amazon technically allows you to publish a print book without an ISBN (they'll assign their own internal identifier), but doing so severely limits your distribution. Your book won't appear in bookstore catalogs, library databases, or any sales channel outside Amazon.

For Ebooks: It Depends

The major ebook retailers do not require ISBNs:

• Amazon KDP — uses its own ASIN identifier. No ISBN required for Kindle ebooks.
• Apple Books — doesn't require an ISBN but recommends one.
• Kobo — ISBN optional.
• Barnes & Noble Press — ISBN optional.

However, if you want your ebook in library systems (OverDrive, Libby, etc.), you need an ISBN. Libraries use ISBNs for cataloging and won't accept ebooks without one.

For Audiobooks: Yes

Audiobooks require their own ISBN, separate from any print or ebook editions. Major audiobook distributors (Findaway Voices, ACX/Audible) require them.

Do I Need an ISBN? Quick Decision Guide

How to Get an ISBN in the United States

In the United States, there is only one authorized ISBN agency: Bowker, operating through its website myidentifiers.com. You cannot buy ISBNs from anywhere else in the US. Any third party offering ISBNs is either reselling Bowker ISBNs (usually at a markup) or providing platform-specific ISBNs (like Amazon or Books.by).

Bowker ISBN Pricing (2026)

Step-by-Step: Buying an ISBN from Bowker

ISBN Price Comparison: Bowker vs Free Options

Here's the complete picture of your ISBN options in the United States. This is the comparison table we wish we had when we first started helping authors publish:

Free ISBNs — What's the Catch?

Books.by is currently the only major self-publishing platform that provides free ISBNs to authors. Other platforms — including Amazon KDP, Draft2Digital, and Barnes & Noble Press — require you to bring your own ISBN (or, in Amazon's case, publish without one using their proprietary ASIN identifier).

So what's the catch with Books.by's free ISBN? There's no hidden cost and no platform lock-in. The only trade-off is the publisher of record.

What "Publisher of Record" Means

Every ISBN is linked to a publisher of record — the entity listed in ISBN databases (Bowker's Books In Print, Nielsen BookData, etc.) as the publisher of that book.

• Books.by free ISBN → Publisher of record: For Authors, Inc (no restrictions — use this ISBN on any platform)
• Your own Bowker ISBN → Publisher of record: your name or imprint

The Real Trade-Off

Here's the honest comparison:

When a Free Books.by ISBN Is Perfectly Fine

• You're publishing your first 1–3 books
• You want to sell across multiple platforms without buying ISBNs
• You don't have a publishing imprint/brand name
• You want to minimize upfront costs
• You're testing the waters with self-publishing

When You Should Buy Your Own

• You're building a publishing imprint or brand
• You plan to publish 10+ books
• You want full metadata control across multiple platforms
• You want your imprint name in bookstore databases
• You're publishing for an organization or company

How to Get an ISBN in Other Countries

The United States is an outlier when it comes to ISBN pricing. In most countries, ISBNs are administered by government agencies and are either free or very inexpensive. Here's a snapshot:

For a complete directory of ISBN agencies by country, visit the International ISBN Agency's directory.

ISBN Rules You Need to Know

ISBNs have specific rules that trip up a lot of self-published authors. Here are the most important ones:

Each Format Needs Its Own ISBN

This is the rule that catches most people off guard. If you publish your book as a paperback, hardcover, ebook, and audiobook, you need four separate ISBNs — one for each format. That's because each format is considered a different "product" in the book supply chain.

New Editions Need New ISBNs

If you substantially revise your book's content (a new edition with significant changes), you need a new ISBN. However, you do not need a new ISBN for minor changes.

When Do I Need a New ISBN?

Other Important Rules

• ISBNs do not expire. Once purchased, they're yours forever. Unassigned ISBNs in your Bowker account remain valid indefinitely.
• ISBNs are not transferable between publishers. If you move from one publisher to another, the old ISBN stays with the old publisher. You need a new ISBN.
• You cannot reuse an ISBN. Once assigned to a title, that ISBN is permanently linked to it — even if the book goes out of print.
• ISBNs are not copyright registration. An ISBN identifies your book as a product. Copyright protects your creative work. They are completely separate systems.

ISBN vs Other Book Identifiers

Authors often confuse ISBNs with other book-related identifiers. Here's a clear breakdown:

Key takeaway: An ISBN is a product identifier. It tells the book supply chain "this specific edition exists." An ASIN is Amazon's version of that, but only works on Amazon. Copyright is a completely different system that protects your creative rights. You may need all of them, but they serve different purposes.

How to Get Your ISBN Barcode

Your print book's back cover needs a barcode — a scannable EAN-13 graphic that encodes your ISBN so bookstores and retailers can scan it at checkout. Here's how to get one without overpaying.

Free Barcode Options

• Books.by — automatically generates a barcode for every print book. No extra cost, no extra steps.
• Amazon KDP — auto-generates a barcode on your cover template.
• Creativindie ISBN Barcode Generator — a free online tool at creativindie.com. Enter your ISBN, download a high-resolution barcode image.
• IngramSpark — generates barcodes as part of their cover template process.

Barcode Placement

Your ISBN barcode should be placed on the back cover of your book, typically in the bottom-right area. Make sure it's within the bleed-safe zone (at least 0.25" from any edge). The standard format is EAN-13, optionally with a 5-digit price extension (called a Bookland EAN) that encodes your book's retail price in the barcode.

Books.by ISBNs: How It Works

Books.by includes free ISBNs with every subscription, making it the simplest way to publish a properly identified book. Unlike other platforms, Books.by ISBNs come with no restrictions — you're free to use them on any platform. Here's exactly how it works:

• Every book gets a free ISBN automatically. When you publish your book on Books.by, an ISBN is assigned at publication time — not when you create the listing.
• No restrictions on use. Your Books.by ISBN is yours to use anywhere — on Amazon, IngramSpark, or any other platform. No lock-in.
• Separate ISBNs for each format. Publishing a paperback and hardcover? Each gets its own ISBN, both free.
• Publisher of record: For Authors, Inc. This is the Books.by parent company. It appears in ISBN databases but has no effect on your copyright or ownership.
• Bring your own ISBN. Already have ISBNs from Bowker? You can use them on Books.by at no extra cost. We support both options.
• Metadata submitted automatically. When you publish, Books.by submits your book's metadata to ISBN databases. No manual data entry at Bowker.
• Barcode generated free. Your print book's ISBN barcode is generated automatically.

For more details on publishing with Books.by, see our Publishing Guide and Pricing page.

Frequently Asked Questions

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