Everything You Need to Know About ISBNs

The self-publishing world is full of important-sounding acronyms, and the International Standard Book Number (ISBN) is one that creates much confusion among new authors.

Technically, you don’t need an ISBN to self-publish your work. However, many distribution channels, such as brick-and-mortar stores, will be off-limits to you unless your book has an ISBN.

What Is an ISBN?

An ISBN is a unique ID that allows booksellers, librarians, readers, publishers—ostensibly, anyone worldwide—to find your book in an online database and look up identifying information, such as country of publication, publisher, title, format, edition, and price. Booksellers rely on ISBNs to organize stock, and most won’t carry your book without an ISBN.

In 1965, British retailer WH Smith had big plans to build a giant, computer-controlled warehouse. But they would need a numerical cataloguing system capable of tracking all titles published in the United Kingdom. They approached Gordon Foster, an Irish computational engineer who had worked as a codebreaker at the famous Bletchley Park. Foster came up with a nine-digit code. With the assistance of the Publishers Association, the “SBN” system was adopted—and all existing UK publisher titles numbered—by 1967. The US adopted the system in 1968, and it became the international standard in 1970. In 2007 the ISBN was converted to the thirteen-digit format we use today.

Currently, there are more than 160 agencies worldwide that are authorized to issue ISBNs. In many countries, ISBNs are provided free of charge through national library systems. In the United States, however, they are privately regulated by Bowker, the country’s largest provider of bibliographical information and the only official ISBN agency. To secure an ISBN in the US, you must purchase one from Bowker or one of their licensed resellers.

How Are ISBNs Generated?

According to the International ISBN Agency, an ISBN has five parts. Each part is separated by a hyphen.

A universal prefix (978 or 979), which simply identifies the number as an ISBN.
A country, geographical group, or language identifier. For example, a book published in English in the United States will be marked by a 0 or 1.
A publisher or publishing group identifier. The number of digits depends on the publisher’s expected title output. A major publishing house will have a very short identifier to save room in the string for longer title identifiers, whereas a self-published author will have a long publisher number because the title identifiers will be shorter.
A title identifier individualized to the edition and format of the title. (An e-book version of your title will have a different title identifierthan the print version.) This identifier can be as short as a single digit.
A single “check digit” that’s generated by an algorithm and based on all preceding numbers. The presence of this digit verifies the accuracy of the ISBN

How Do I Get an ISBN?

Get a free, limited-use ISBN through Kindle Direct Publishing (KDP).When you publish a paperback through Amazon’s KDP platform, you can request a free ISBN. KDP will assign the number, which will be registered with BooksInPrint.com®, the database maintained by Bowker.
This is the simplest and most economical option available, but there is a major drawback.

You can use your ISBN only on the KDP platform for distribution to Amazon and its distribution partners. If you want to take advantage of other distribution services or sell at retailers, you’ll need to purchase a second ISBN from Bowker. (Creating multiple ISBNs for a singular title/format is problematic and frowned upon.)
Purchase a custom ISBN from Bowker. And as mentioned, this is the only way to get your book into brick-and-mortar stores and distribution channels outside Amazon’s network.
Also, purchasing your own ISBN gives you complete control over your book’s bibliographical record. With a KDP-issued ISBN, the publisher field will be generic: “Independently published.” By purchasing your own ISBN, you are effectively becoming your own publisher. If you don’t have a company name, you can simply register your personal name as publisher.

In the US, you must purchase your ISBN directly from Bowker through myidentifiers.com. (If you are outside of the United States, find your local ISBN Agency here.)

Do I Need More than One ISBN?

You can buy a single ISBN, or you can buy them in bulk (10, 100, or 1,000). If you plan to publish in multiple formats (paperback, hard cover, and e-book), you’ll need individual ISBNs for each version. You’ll also need additional ISBNs for translations, audiobooks, and updated editions. If you publish a series of books, you’ll need separate ISBNs for each volume.

You won’t need a new ISBN if you change the price, cover, vendor, or make minor corrections to the text. But significant alterations, such as changing the title, trim size, or binding, will require new ISBNs.

ISBNs aren’t transferable, so once they’re registered to a title, you can’t recycle them even if the book goes out of print.

Are ISBNs the Same as ASINs or LCCNs?

No. ASINs are exclusively used by Amazon to manage the products they sell on their website. ASINs are typically shorter than ISBNs, with ten digits, and have no application outside Amazon’s organization.

LCCN stands for Library of Congress Control Number. These identifiers are issued to books that are accepted into the Library of Congress’s collection. Librarians use LCCNs to search for titles, and since you must apply for one, obtaining an LCCN lends an air of professionalism to your work. But an LCCN is not a substitute for an ISBN, and you do not need an LCCN to sell your book online or in stores.