International Standard Book Number
The International Standard Book Number is a numeric commercial book identifier which is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency.
An ISBN is assigned to each separate edition and variation of a publication. For example, an e-book, a paperback and a hardcover edition of the same book will each have a different ISBN. The ISBN is ten digits long if assigned before 2007, and thirteen digits long if assigned on or after 1 January 2007. The method of assigning an ISBN is nation-specific and varies between countries, often depending on how large the publishing industry is within a country.
The initial ISBN identification format was devised in 1967, based upon the 9-digit Standard Book Numbering created in 1966. The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO 2108.
Privately published books sometimes appear without an ISBN. The International ISBN Agency sometimes assigns such books ISBNs on its own initiative.
Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines and newspapers. The International Standard Music Number covers musical scores.
HistoryThe Standard Book Number is a commercial system using nine-digit code numbers to identify books. It was created by Gordon Foster, Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers WHSmith and others in 1965. The ISBN identification format was conceived in 1967 in the United Kingdom by David Whitaker and in 1968 in the United States by Emery Koltay.
The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO 2108. The United Kingdom continued to use the nine-digit SBN code until 1974. ISO has appointed the International ISBN Agency as the registration authority for ISBN worldwide and the ISBN Standard is developed under the control of ISO Technical Committee 46/Subcommittee 9 TC 46/SC 9. The ISO on-line facility only refers back to 1978.
An SBN may be converted to an ISBN by prefixing the digit "0". For example, the second edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has, where "340" indicates the publisher, "01381" is the serial number assigned by the publisher, and "8" is the check digit. By prefixing a zero, this can be converted to ; the check digit does not need to be re-calculated. Some publishers, such as Ballantine Books, would sometimes use 12-digit SBNs where the last three digits indicated the price of the book; for example, Woodstock Handmade Houses had a 12-digit Standard Book Number of 345-24223-8-595, and it cost.
Since 1 January 2007, ISBNs have contained thirteen digits, a format that is compatible with "Bookland" European Article Numbers, which have 13 digits.
OverviewA separate ISBN is assigned to each edition and variation of a publication. For example, an ebook, audiobook, paperback, and hardcover edition of the same book will each have a different ISBN assigned to it. The ISBN is thirteen digits long if assigned on or after 1 January 2007, and ten digits long if assigned before 2007. An International Standard Book Number consists of four parts or five parts.
Section 5 of the International ISBN Agency's official user manual describes the structure of the 13-digit ISBN, as follows:
- for a 13-digit ISBN, a prefix element – a GS1 prefix: so far 978 or 979 have been made available by GS1,
- the registration group element,
- the registrant element,
- the publication element, and
- a checksum character or check digit.
ISBN is most often used alongside other special identifiers to describe references in Wikipedia, and can help to find the same sources with different descriptions in various language versions.
How ISBNs are issuedISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for that country or territory regardless of the publication language. The ranges of ISBNs assigned to any particular country are based on the publishing profile of the country concerned, and so the ranges will vary depending on the number of books and the number, type, and size of publishers that are active. Some ISBN registration agencies are based in national libraries or within ministries of culture and thus may receive direct funding from government to support their services. In other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded.
A full directory of ISBN agencies is available on the International ISBN Agency website. Partial listing:
- Australia – the commercial library services agency Thorpe-Bowker;
- Brazil – The National Library of Brazil;
- Brazil – Câmara Brasileira do Livro;
- Canada – English Library and Archives Canada, a government agency; French Bibliothèque et Archives nationales du Québec;
- Colombia – Cámara Colombiana del Libro, an NGO;
- Hong Kong – Books Registration Office, under the Hong Kong Public Libraries;
- India – The Raja Rammohun Roy National Agency for ISBN, under Department of Higher Education, a constituent of the Ministry of Human Resource Development;
- Iceland – Landsbókasafn ;
- Israel – The Israel Center for Libraries;
- Italy – EDISER srl, owned by Associazione Italiana Editori ;
- Maldives – The National Bureau of Classification ;
- Malta – The National Book Council ;
- Morocco – The National Library of Morocco
- New Zealand – The National Library of New Zealand;
- Pakistan – National Library of Pakistan
- Philippines – National Library of the Philippines;
- South Africa – National Library of South Africa
- Spain –
- Turkey – General Directorate of Libraries and Publications, a branch of the Ministry of Culture;
- United Kingdom and Republic of Ireland -Nielsen Book Services Ltd, part of Nielsen Holdings N.V.;
- United States – R. R. Bowker.
Registration group identifier
Within the 979 prefix element, the registration group identifier 0 is reserved for compatibility with International Standard Music Numbers, but such material is not actually assigned an ISBN. The registration group identifiers within prefix element 979 that have been assigned are 8 for the United States of America, 10 for France, 11 for the Republic of Korea, and 12 for Italy.
The original 9-digit standard book number had no registration group identifier, but prefixing a zero to a 9-digit SBN creates a valid 10-digit ISBN.
Registrant elementThe national ISBN agency assigns the registrant element and an accompanying series of ISBNs within that registrant element to the publisher; the publisher then allocates one of the ISBNs to each of its books. In most countries, a book publisher is not legally required to assign an ISBN, although most large bookstores only handle publications that have ISBNs assigned to them.
A listing of more than 900,000 assigned publisher codes is published, and can be ordered in book form. The web site of the ISBN agency does not offer any free method of looking up publisher codes. Partial lists have been compiled for the English-language groups: identifier 0 and identifier 1.
Publishers receive blocks of ISBNs, with larger blocks allotted to publishers expecting to need them; a small publisher may receive ISBNs of one or more digits for the registration group identifier, several digits for the registrant, and a single digit for the publication element. Once that block of ISBNs is used, the publisher may receive another block of ISBNs, with a different registrant element. Consequently, a publisher may have different allotted registrant elements. There also may be more than one registration group identifier used in a country. This might occur once all the registrant elements from a particular registration group have been allocated to publishers.
By using variable block lengths, registration agencies are able to customise the allocations of ISBNs that they make to publishers. For example, a large publisher may be given a block of ISBNs where fewer digits are allocated for the registrant element and many digits are allocated for the publication element; likewise, countries publishing many titles have few allocated digits for the registration group identifier and many for the registrant and publication elements. Here are some sample
|ISBN||Country or area||Publisher|
|Czech Republic; Slovakia||Taita Publishers|
|Brazil||Companhia das Letras|
|English-speaking area||Simon Wallenberg Press|
|English-speaking area||Frederick Ungar|
|English-speaking area||J. A. Allen & Co.|
|English-speaking area||Edupedia Publications Pvt Ltd.|
|English-speaking area||KT Publishing|
Pattern for English language ISBNsEnglish-language registration group elements are 0 and 1. These two registration group elements are divided into registrant elements in a systematic pattern, which allows their length to be determined, as follows:
Check digitsA check digit is a form of redundancy check used for error detection, the decimal equivalent of a binary check bit. It consists of a single digit computed from the other digits in the number. The method for the 10-digit ISBN is an extension of that for SBNs, so the two systems are compatible; an SBN prefixed with a zero will give the same check digit as the SBN without the zero. The check digit is base eleven, and can be an integer between 0 and 9, or an 'X'. The system for 13-digit ISBNs is not compatible with SBNs and will, in general, give a different check digit from the corresponding 10-digit ISBN, so does not provide the same protection against transposition. This is because the 13-digit code was required to be compatible with the EAN format, and hence could not contain an 'X'.
According to the 2001 edition of the International ISBN Agency's official user manual, the
ISBN-10 check digits
For example, for an
Formally, using modular arithmetic, this is rendered:
It is also true for
Formally, this is rendered:
The two most common errors in handling an ISBN are a single altered digit or the transposition of adjacent digits. It can be proven mathematically that all pairs of valid
In contrast, it is possible for other types of error, such as two altered non-transposed digits, or three altered digits, to result in a valid ISBN.
Each of the first nine digits of the 10-digit ISBN—excluding the check digit itself—is multiplied by its weight, descending from 10 to 2, and the sum of these nine products found. The value of the check digit is simply the one number between 0 and 10 which, when added to this sum, means the total is a multiple of 11.
ISBN-10 check digit calculation
For example, the check digit for an
Adding 2 to 130 gives a multiple of 11 – this is the only number between 0 and 10 which does so. Therefore, the check digit has to be 2, and the complete sequence is
Alternatively, modular arithmetic is convenient for calculating the check digit using modulus 11. The remainder of this sum when it is divided by 11, is computed. This remainder plus the check digit must equal either 0 or 11. Therefore, the check digit is modulo 11. Taking the remainder modulo 11 a second time accounts for the possibility that the first remainder is 0. Without the second modulo operation, the calculation could result in a check digit value of = 11, which is invalid.
For example, the check digit for the
Thus the check digit is 2.
It is possible to avoid the multiplications in a software implementation by using two accumulators. Repeatedly adding
scomputes the necessary multiples:
// Returns ISBN error syndrome, zero for a valid ISBN, non-zero for an invalid one.
// digits must be between 0 and 10.
The modular reduction can be done once at the end, as shown above, or
tcould be reduced by a conditional subtract after each addition.
Appendix 1 of the International ISBN Agency's official user manual describes how the 13-digit ISBN check digit is calculated. The
ISBN-13 check digit calculation
Formally, using modular arithmetic, this is rendered:
The calculation of an
For example, the
s = 9×1 + 7×3 + 8×1 + 0×3 + 3×1 + 0×3 + 6×1 + 4×3 + 0×1 + 6×3 + 1×1 + 5×3
= 9 + 21 + 8 + 0 + 3 + 0 + 6 + 12 + 0 + 18 + 1 + 15
93 / 10 = 9 remainder 3
10 – 3 = 7
Thus, the check digit is 7, and the complete sequence is
In general, the
This check system – similar to the UPC check digit formula – does not catch all errors of adjacent digit transposition. Specifically, if the difference between two adjacent digits is 5, the check digit will not catch their transposition. For instance, the above example allows this situation with the 6 followed by a 1. The correct order contributes 3×6+1×1 = 19 to the sum; while, if the digits are transposed, the contribution of those two digits will be 3×1+1×6 = 9. However, 19 and 9 are congruent modulo 10, and so produce the same, final result: both ISBNs will have a check digit of 7. The
Additionally, if the sum of the 2nd, 4th, 6th, 8th, 10th, and 12th digits is tripled then added to the remaining digits, the total will always be divisible by 10.
ISBN-10 to ISBN-13 conversion
Errors in usageand libraries have varied policies about the use of the ISBN check digit. Publishers sometimes fail to check the correspondence of a book title and its ISBN before publishing it; that failure causes book identification problems for libraries, booksellers, and readers. For example, is shared by two books – Ninja gaiden®: a novel based on the best-selling game by Tecmo and Wacky laws, both published by Scholastic.
Most libraries and booksellers display the book record for an invalid ISBN issued by the publisher. The Library of Congress catalogue contains books published with invalid ISBNs, which it usually tags with the phrase "Cancelled ISBN". However, book-ordering systems such as Amazon.com will not search for a book if an invalid ISBN is entered to its search engine. OCLC often indexes by invalid ISBNs, if the book is indexed in that way by a member library.
eISBNOnly the term "ISBN" should be used; the terms "eISBN" and "e-ISBN" have historically been sources of confusion and should be avoided. If a book exists in one or more digital formats, each of those formats must have its own ISBN. In other words, each of the three separate EPUB, Amazon Kindle, and PDF formats of a particular book will have its own specific ISBN. They should not share the ISBN of the paper version, and there is no generic "eISBN" which encompasses all the e-book formats for a title.
EAN format used in barcodes, and upgradingCurrently the barcodes on a book's back cover are EAN-13; they may have a separate barcode encoding five digits called an EAN-5 for the currency and the recommended retail price. For 10-digit ISBNs, the number "978", the Bookland "country code", is prefixed to the ISBN in the barcode data, and the check digit is recalculated according to the EAN-13 formula.
Partly because of an expected shortage in certain ISBN categories, the International Organization for Standardization decided to migrate to a 13-digit ISBN. The process began on 1 January 2005 and was planned to conclude on 1 January 2007., all the 13-digit ISBNs began with 978. As the 978 ISBN supply is exhausted, the 979 prefix was introduced. Part of the 979 prefix is reserved for use with the Musicland code for musical scores with an ISMN. The 10-digit ISMN codes differed visually as they began with an "M" letter; the bar code represents the "M" as a zero, and for checksum purposes it counted as a 3. All ISMNs are now thirteen digits commencing ; to will be used by ISBN.
Publisher identification code numbers are unlikely to be the same in the 978 and 979 ISBNs, likewise, there is no guarantee that language area code numbers will be the same. Moreover, the 10-digit ISBN check digit generally is not the same as the 13-digit ISBN check digit. Because the GTIN-13 is part of the Global Trade Item Number system, the 13-digit ISBN falls within the 14-digit data field range.
Barcode format compatibility is maintained, because the