What Is an ISBN

Glossary > ISBN

💬 Definition of ISBN:

ISBN stands for International Standard Book Number. It is a unique numerical identifier assigned to each published book used to identify and distinguish it from other books with similar titles or subjects. 

Related questions about ISBN:

What is an ISBN formed of?

The ISBN is usually a 13-digit number (since 2007) comprising five parts: 

  • a prefix element
  • a group or country identifier, a publisher identifier
  • an item identifier
  • a check digit

The first three elements identify the country, language, and publisher of the book, while the item identifier and check digit are used to identify the specific edition or printing of the book.

How to get an ISBN?

ISBNs are assigned to books by ISBN agencies responsible for assigning, registering, and managing ISBNs for publishers and self-publishers.

Acquiring an ISBN depends on your location. The International ISBN Agency gives the registration identifiers to local authorities, who decide what to do with them.

For example: 

  • In the United States and Australia, you can get a Bowker ISBN which costs around $125 to $250.
  • In the UK, you can get an ISBN from Nielson, which costs around £89 to £149.
  • In other countries (e.g., Hungary), getting one is free.

Is it mandatory to have an ISBN?

Having an ISBN for every book is not mandatory. They're required for print books, but they're not necessary for ebooks and audiobooks. Still, it is highly recommended, especially for books that are intended for commercial distribution. 

In the self-publishing industry, most stores will assign their own identifiers. For example, Amazon uses ASIN. PublishDrive uses PUI

Journals, magazines, and other publications don't need an ISBN. They have an ISSN number instead.

How to get an ISBN for free?

Some publishing platforms such as Kindle Direct, CreateSpace, Lulu, or PublishDrive offer their own identification numbers for free when you use their services for publishing. These identifiers are unique to the platform and serve the same purpose as an ISBN. In case your country doesn't provide ISBNs for free, you can still obtain them at no cost through such platforms.

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