4. Structure of the ISBN

From 1 January 2007, national ISBN agencies shall only provide ISBNs that consist of 13

digits, comprising the following elements:

  Prefix element

  Registration group element

  Registrant element

  Publication element

  Check digit

When printed, the ISBN is always preceded by the letters  ISBN . 

Note: 

In countries where the Latin alphabet is not used, an abbreviation in the characters

of the local script may be used 

in addition 

to the Latin letters  ISBN . 

The ISBN is divided into five elements, three of them of variable length; the first and last

elements are of fixed length. The elements must each be separated clearly by hyphens or

spaces when displayed in 

human readable

 form: 

ISBN 978 0 571 08989 5 

or

ISBN 978 0 571 08989 5

Note: 

The use of hyphens or spaces has no lexical significance and is purely to enhance

readability. 

The number of digits in the second, third, and fourth elements of the ISBN (registration

group element, registrant element, publication element) varies. The length of the

registration group element and of the registrant element is relative to the anticipated

publishing output of the registration group or registrant. When these elements are short in

length it indicates that the output of the registration group or the registrant (or both) is

expected to be a large number of publications. 

4.1 Prefix element

The first element of the ISBN is a three digit number that is made available by EAN

International. Prefixes that have already been made available by EAN International are

978 and 979, but there may be a further prefix allocation made in the future as required to

ensure the continued capacity of the ISBN system. 

EXAMPLE: 978

4.2 Registration group element

The second element of the ISBN identifies the country, geographical region, or language

area participating in the ISBN system. Some members of the ISBN system form language

areas (e.g., registration group number 3 = German language group); others form regional

units (e.g., registration group number 982 = South Pacific). The length of this element

varies but may comprise up to 5 digits. 

Registration group elements are allocated by the International ISBN Agency. 

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