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International Standard Book Number (ISBN)

One for the geeks... everything you ever wanted to know about ISBNs but were too sensible to ask.

The Quick Answer

An ISBN is a code that uniquely identifies a book, giving information on country of origin and publisher, as well as providing error checking.

On BookLore ISBNs are given with the following codes:

  • PB - Paperback
  • HB - Hardback
  • EB - E-Book (Digital)

The Long Answer

An ISBN is assigned to each edition and variation (except reprints) of a book. The ISBN is 13 digits long (ISBN-13) if assigned after 1st January 2007, and 10 digits long (ISBN-10) if assigned before 2007.

The International Standard Book Number has been a remarkable success story since its inception in 1968 as the 'Standard Book Number' (SBN) in the United Kingdom. Within a year the SBN was transformed into the International SBN, and was extended from a nine-digit to a ten-digit number. From 1st January 2007 ISBNs consist of a thirteen-digit number. Since its ratification by ISO as International Standard 2108 in 1970, the international coordination of the ISBN system has been the responsibility of the International ISBN Agency in Berlin, a unit within the Berlin State Library. At present, 166 countries are members of the ISBN system.

ISBNs that consist of 13 digits comprise the following five elements:

[1] Prefix Element - Fixed Length
[2] Registration Group Element - Variable Length
[3] Registrant Element - Variable Length
[4] Publication Element - Variable Length
[5] Check Digit - Fixed Length

When printed, the ISBN is always preceded by the letters 'ISBN'. The five elements must each be separated clearly by hyphens or spaces when displayed in human readable form, for example:

ISBN 978-0-571-08989-5
ISBN 978 0 571 08989 5

Note: The use of hyphens or spaces has no lexical significance and is purely to enhance readability.

[1] Prefix Element - Fixed Length

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, for example:


[2] Registration Group Element - Variable Length

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 and may comprise up to 5 digits. Registration group elements are allocated by the International ISBN Agency. For example:


A list of country codes are included at the end of this article for those that are interested.

[3] Registrant Element - Variable Length

The third element of the ISBN identifies a particular publisher or imprint within a registration group. The length of this element varies in direct relationship to the anticipated output of the publisher and may comprise up to 7 digits. Publishers with the largest expected title outputs are assigned the shortest registrant elements or block size and vice versa. For example:


Potential registrants apply to the ISBN group agency responsible for the management of the ISBN system within the country, region, or language group where they are based in order to be assigned registrant elements that are unique to them. Once they have exhausted the allocation of ISBNs that is linked to their registrant element, they may be assigned an additional registrant element providing further allocations of ISBNs.

[4] Publication Element - Variable Length

The fourth element of the ISBN identifies a specific edition of a publication by a specific publisher. The length of this element varies in direct relationship to the anticipated output of the publisher concerned and may comprise up to 6 digits. Publishers with the largest expected title outputs are assigned the longest publication elements and vice versa. To ensure that the correct length of the ISBN is maintained, blank digits are represented by leading zeros. For example:


[5] Check Digit - Fixed Length

The fifth element of the ISBN is the check digit. This is calculated using a modulus 10 algorithm. Each of the first 12 digits of the ISBN is alternately multiplied by 1 and 3. The check digit is equal to 10 minus the remainder resulting from dividing the sum of the weighted products of the first 12 digits by 10 with one exception. If this calculation results in an apparent check digit of 10, the check digit is 0. For example:


For a full mathematical explanation of the ISBN-10 and ISBN-13 check digits and examples see:

Positioning of Hyphens /Spaces

For English publications the Hyphens or Spaces are positioned as follows, ignoring the ISBN-13 Prefix Element:


Publisher ID

If number ranges
are between:

Insert hyphen
after the:

Block Size




3rd digit





4th digit





5th digit





6th digit





7th digit





8th digit





3rd digit





4th digit





5th digit





6th digit





7th digit





8th digit


Uses of ISBNs

The ISBN is used in all branches of the book supply chain.

The ISBN in publishing houses is used for:

    • Identifying firm publication projects from receipt of author's manuscript to delivery of final publication
    • Publication identification in publishers' catalogues and advertisements
    • Listing in printed and electronic directories and on Internet sites
    • Stock control
    • Management of royalties
    • Ordering
    • Accounting and billing
    • Monitoring sales data
    • Producing statistics
    • Handling of returns

The ISBN in bibliographic data services, distribution centres, and wholesalers is used for:

    • Building databases of publications both in- and out-of-print
    • Generating bibliographic products and catalogues from these databases of publications for the book trade
    • Ordering services based on electronic communication systems such as EDI (electronic data interchange) or via the Internet
    • Stock control
    • Monitoring internal logistic processes
    • Accounting and billing
    • Producing sales data
    • Returns administration
    • Producing subject lists and catalogues

The ISBN in centralised service organisations for libraries (producing ready-to-borrow copies) is used for:

    • Ordering from the publishers or wholesalers
    • Processing orders from libraries
    • Stock control
    • Monitoring internal logistic processes
    • Accounting and billing
    • Administration of rebinding processes

The ISBN in bookshops is used for:

    • Bibliographic searches
    • Tracing addresses of publishers or distributors
    • Ordering and reordering processes based on electronic communication systems such as EDI (electronic data interchange) or via the Internet
    • Stock administration
    • Accounting and billing the end consumer
    • Electronic point-of-sale system (EPOS)

The ISBN in libraries is used for:

    • Information retrieval
    • Ordering
    • Copy-cataloguing
    • Lending statistics
    • National lending right
    • Inter-library loans

ISBN Country Codes

The following list gives the group/country identifier for each country:

0/1 English - (UK, US, Australia, NZ, Canada, South Africa, Zimbabwe) [Ireland, Puerto Rico, Swaziland]
2 French - (France, Belgium, Canada, Switzerland)[and Luxembourg]
3 German - (Germany, Austria, Switzerland)
4 Japan
5 USSR [Now identified as Russian Federation, including these countries, many of which also have other codes: Azerbaijan, Tajikistan, Turkmenistan, Uzbekistan, Armenia (9930), Belarus (985), Estonia (9985), Georgia (99928), Kazakhstan (9965), Kyrgyzstan (9967), Latvia (9984), Lithuania (9986), Moldova (9975), Ukraine (966)]
7 China
80 Czechoslovakia [Czech Republic and Slovakia]
81 India (see also 93)
82 Norway
83 Poland
84 Spain
85 Brazil
86 Yugoslavia [Yugoslavia and Bosnia and Herzegovina (9958), Croatia (953), Macedonia (9989),Slovenia (961)]
87 Denmark
88 Italian - (Italy, Switzerland)
89 South Korea
90 Dutch/Flemish
91 Sweden
92 International (UNESCO)
93 India (see also 81)
950 Argentina
951 Finland
952 Finland
953 Croatia
954 Bulgaria
955 Sri Lanka
956 Chile
957 Taiwan [see also 986]
958 Colombia
959 Cuba
960 Greece
961 Slovenia
962 Hong Kong
963 Hungary
964 Iran
965 Israel
966 Ukraine
967 Malaysia (see also 983)
968 Mexico (see also 970)
969 Pakistan
970 Mexico (see also 968)
971 Philippines
972 Portugal
973 Romania
974 Thailand
975 Turkey
977 Egypt
978 Nigeria
979 Indonesia
980 Venezuela
981 Singapore (see also 9971)
983 Malaysia (see also 967)
984 Bangladesh
985 Belarus986 Taiwan [see also 957; new]
987 Argentina
9952 Azerbaijan
9953 Lebanon
9954 Morocco (see also 9981))
9955 Lithuania (See also 9986)
9956 Cameroon
9957 Jordan
9958 Bosnia and Herzegovina
9959 Libya
9960 Saudi Arabia
9961 Algeria
9962 Panama
9963 Cyprus
9964 Ghana
9965 Kazakhstan
9966 Kenya
9967 Kyrgyzstan
9968 Costa Rica (see also 9977)
9970 Uganda
9971 Singapore (see also 981)
9972 Syria
9973 Tunisia
9974 Uruguay
9975 Moldova
9976 Tanzania (see also 9987)
9977 Costa Rica (see also 9968)
9978 Ecuador
9979 Iceland
9980 Papua New Guinea
9981 Morocco [see also 9954]
9982 Zambia
9983 Gambia
9984 Latvia
9985 Estonia
9986 Lithuania [see also 9955]
9987 Tanzania (see also 9976)
9988 Ghana
9989 Macedonia
99901 Bahrain
99903 Mauritius
99904 Netherlands Antilles [Aruba, Neth. Antilles]
99908 Malawi
99909 Malta [see also 99932]
99910 Sierra Leone
99911 Lesotho
99912 Botswana
99913 Andorra (see also 99920)
99914 Suriname
99915 Maldives
99916 Namibia
99917 Brunei [Brunei Darussalam]
99918 Faroe Islands
99919 Benin
99920 Andorra (see also 99913)
99921 Qatar
99922 Guatemala
99923 El Salvador
99924 Nicaragua
99925 Paraguay
99926 Honduras
99927 Albania
99928 Georgia
99929 Mongolia
99930 Armenia
99931 Seychelles
99932 Malta (see also 99909)
99933 Nepal
99935 Dominican Republic
99936 Bhutan
99937 Macau

We gratefully acknowledge the following Websites as sources for this article:

The International ISBN Agency


Weisstein, Eric W. "ISBN." From MathWorld--A Wolfram Web Resource.

XML Schema simple Type Definition of an ISBN. Authors: Roger Costello and Roger Sperberg

Nigel - 22nd March 2008

Column Ends