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ISBN and ISSN Systems: General Information and Resources

Explanations and resources for ISBNs and ISSNs.

ISBN and ISSN Standards

Barcode with text that reads ISBN and ISSN SystemsInternational Standard Book Number (ISBN) is a national and international standard identification number for uniquely identifying books, i.e., publications that are not intended to continue indefinitely. The International Standard Serial Number (ISSN) is a national and international standard for serial publications. Both number standards can apply to electronic or print versions.


This resource guide provides general information and a history on the ISBN and ISSN standards. 

ISBN General Information

The International Standard Book Number (ISBN) is a 13-digit number that uniquely identifies books and book-like products published internationally. The ISBN is intended for a monographic publication: text that stands on its own as a product, whether printed, audio or electronic. ISBNs are never assigned to music, performances or images, such as art prints or photographs. ISBNs are not assigned to magazines, academic journals or other periodicals. However, if a single issue of a periodical is being sold as a book, then that issue alone may be assigned an ISBN. 

When participating in the ISBN standard, publishers and self-publishers are required to report all information about titles to which they have assigned ISBNs. For more than thirty years, ISBNs were 10 digits long. On January 1, 2007 the ISBN system switched to a 13-digit format. Now all ISBNs are 13-digits long. If you were assigned 10-digit ISBNs, you can convert them to the 13-digit format at the converter found on the ISBN website. A 10-digit ISBN cannot be converted to 13-digits merely by placing three digits in front of the 10-digit number. There is an algorithm that frequently results in a change of the last digit of the ISBN.

ISBNs beginning 979 will not be issued in the United States for at least several years until current inventories of ISBNs are depleted. When they are assigned, they will not replace those beginning with 978.

  • ISBNs beginning 978 and 979 will coexist in the book industry for a number of years.
  • 978 ISBNs cannot be converted to 979 ISBNs.
  • 979 ISBNs are not convertible to a 10-digit format and exist only in a 13-digit format.

ISBN Resources

ISSN General Information

The ISSN is a U.S. standard and an international standard. The number itself -- unlike the coded digits of the ISBN -- has no significance other than as a brief, unique, and unambiguous identifier; an ISSN consists of eight digits, specifically two groups of four digits, in Arabic numerals 0 to 9, except for the last -- or check -- digit, which can be an X. Its proper reference is for the two groups of four digits to be separated by a hyphen and preceded by the letters ISSN.

Assignment of ISSNs is handled by the U.S. ISSN Center at the Library of Congress and is free. There is no charge associated with the use of the ISSN. An ISSN application form may be completed online. Enter the required information and then email or fax the form (in the interests of conserving paper and bandwidth, please limit faxes or email attachments to no more than five pages), or mail the application by U.S. mail or private carrier. A suitable representation of the publication must accompany the application. For print serials a sample issue or photocopy of the title page, cover, or masthead should be provided. For electronic serials in a tangible form such as CD-ROM or floppy disk, an actual issue and printouts of title screens should be submitted. For online serials, provide an appropriate URL or e-mail actual issues or mock-ups which will accompany the application form.

ISSN Resources