ISBN 13: Structure explained - this is how the number is composed

Until 2007, the ISBN had ten digits, since then it has been 13. This change has been mandatory for all ISBNs since that date. We explain the structure of the thirteen-digit number.

Nothing is left to chance: The ISBN is structured according to a clear system.

We have already explained the difference between ISBN 10 and 13 here, including the reasoning behind the change.

ISBN: Structure with five different segments

The ISBN can be divided into five successive segments:

• The first three digits indicate the ISBN prefix 978 or 979.
• On the fourth digit is the country code (Germany = 3).
• The next four digits stand for the publisher number.
• The next four digits consist of the title number.
• At the end is the one-digit check digit.

With this structure, the ISBN from a cryptic numerical code to a number with a unique statement. If you are wondering whether eBooks need an ISBN, you can find the answer here.