ISBN — International Standard Book Number

ISBN stands for International Standard Book Number, and is a barcode standard.

An ISBN is a unique, 13-digit code used to identify a specific book or a specific edition of a book. Each separate format (such as hardcover, paperback, and e-book) requires its own distinct ISBN. Unchanged reprints don't get a new ISBN, but other variations, like new editions, do.

ISBN is intended to be a unique book identifier. This is important for retailers, libraries and others involved in supply chains for books. Book publishers obtain ISBNs from their respective national ISBN agency, the entity responsible for the implementation of the ISBN system in the country where they are based. Books that are published privately might not have an ISBN, although the ISBN agency may take the initiative to assign one.

Structure of an ISBN

  • The first 3 digits are always always 978 or 979, and are called the prefix.
  • The next 1 to 5 digits are the “registration group” and they identify the country, geographic area, or language region.
  • The registrant or publisher element identifies the specific publishing house.
  • The publication or title element identifies a specific edition and format of the publication.
  • The final digit in an ISBN is always a check-digit (calculated via a weighted sum), which adds no unique information but helps to prevent errors.

History

In 1965, British bookseller WHSmith announced plans for a numbering system, and in 1966, the 9-digit Standard Book Numbering (SBN) format was created.

ISBN was devised in 1967. It was based on the SBN format. Adding a zero at the beginning of a 9-digit SBN converts it to a 10-digit ISBN. The International Organization for Standardization (ISO) developed the 10-digit format, which was introduced in 1970, published as ISO 2108.

The 10-digit standard lasted until the end of 2006. ISBNs assigned on or after 1 January 2007 have 13 digits. These 13-digit ISBNs are compatible with the EAN (European Article Number or International Article Number) system, and is thus interoperable with that broader barcoding system used to track and identify all kinds of products all across the globe.

A legacy 10-digit ISBN can be reliably converted into the modern, 13-digit ISBN (EAN-13) format. To convert a 10-digit ISBN to its corresponding 13-digit number, you need only prepend the three digits 978 and then recalculate the last digit (the check-digit), according to the EAN standard.

Find Books All Over the World

Go-UPC indexes product information from all over the planet — including titles, images, and other info on millions of books. You can use our search tool to find such information from any ISBN.

If you have a routine use for obtaining book information, you may want to look at our API (great for book-related apps and software) or our Bulk Lookup Service for large, one-time lookups.