Library of Congress
U.S. ISSN Center
101 Independence Ave., S.E.
Washington, DC 20540-4284
Tel.: (202) 707-6452
Fax: (202) 707-6333
Monday-Friday 9:30 am-5:00 pm
Calculating the Check Digit in an ISSN | Bar Codes for Serials
Serials are print or non-print publications issued in parts, usually bearing issue numbers and/or dates. A serial is expected to continue indefinitely. Serials include magazines, newspapers, annuals (such as reports, yearbooks, and directories), journals, memoirs, proceedings, transactions of societies, and monographic series.
International Standard Serial Numbering
The various and constant changes to which serials are subject, combined with the large growth in the world's publishing output, prompted the development of a standard (ISO 3297-1975; ANSI Z39.9-1979) for the identification of serials: the International Standard Serial Number (ISSN).
A single ISSN uniquely identifies a title regardless of language or country in which published, without the burden of a complex bibliographic description. The ISSN itself has no significance other than the unique identification of a serial.
An ISSN is eight digits long. Always displayed this way: ISSN 1234-5679, the first seven digits serve as the title number and the eighth is a check digit which provides an efficient means for discovering transcription errors. The system used for calculating the check digit sometimes requires a check number of 10, in which case, to prevent a nine-digit ISSN, the roman numeral "X" is substituted.
For each serial with an ISSN there is a corresponding "key title"--a commonly acceptable form of the title established at the time of ISSN assignment. The title provides a benchmark which serves to regulate the assignment of ISSN: if the title of a serial changes, a new ISSN must be assigned.
Administration of the ISSN
The coordination of the ISSN is international, with registration initiated at the national level where serials are published. The U.S. ISSN Center within the Library of Congress serves the United States in the ISSN network. The ISSN International Centre located in Paris coordinates the network. The U.S. ISSN Center is responsible for registering and providing ISSN for serials published in the United States and for promoting use of the ISSN.
Advantages of Use
The ISSN should be as basic a part of a serial as the title. The advantages of using it are abundant and the more the number is used the more benefits will accrue.
- ISSN provides a useful and economical method of communication between publishers and suppliers, making trade distribution systems faster and more efficient.
- The ISSN results in accurate citing of serials by scholars, researchers, abstracters, and librarians.
- As a standard numeric identification code, the ISSN is eminently suitable for computer use in fulfilling the need for file update and linkage, retrieval, and transmittal of data.
- ISSN is used in libraries for identifying titles, ordering and checking in, and claiming serials.
- ISSN simplifies interlibrary loan systems and union catalog reporting and listing.
- The U.S. Postal Service uses the ISSN to regulate certain publications mailed at second-class and controlled circulation rates.
- The ISSN is an integral component of the journal article citation used to monitor payments to the Copyright Clearance Center, Inc.
- All ISSN registrations are maintained in an international data base and are made available in the ISSN Register online. The ISSN portal and other products are described in a document maintained by the ISSN International Centre: ISSN products.
How to Obtain an ISSN
Instructions for U.S. publishers
The assignment of the ISSN is free in the U.S. and there is no charge associated with its use. (However, the Library of Congress incurs substantial costs to staff and maintain the U.S. ISSN Center. Additionally, the Library of Congress is assessed a considerable fee to belong to the ISSN Network.)
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 to firstname.lastname@example.org.
When requesting an ISSN for an already-published serial, send a sample issue or copy of the cover, title page, and masthead as appropriate to: Library of Congress, U.S. ISSN Center, 101 Independence Avenue, SE, Washington, DC 20540-4284.
Except for microform reproductions, separate ISSN are generally required for serials issued in different physical formats, (e.g., print, CD-ROM, online, etc.). Separate ISSN are also required for serials issued in different language, geographic, or audience editions. Please complete a separate application form for each edition or note the different editions in the "Additional information, comments, questions" section of the application form.
For prepublication requests, a mock-up or artist's conception of the same identifying parts of the publication should be sent, if possible. In these "v. 1, no. 1" cases, a follow-up sample issue or surrogate of the actual serial must be sent directly to the U.S. ISSN Center after publication has begun.
To fulfill its purpose, the ISSN should be displayed prominently on every issue, preferably in the top right corner of the cover. It is acceptable, however, for the number to appear elsewhere on the publication (usually in the masthead area). Various user groups--particularly the U.S. Postal Service--have specific printing regulations which must be adhered to.
If the serial has an International Standard Book Number (ISBN) for the individual volumes within a series, in addition to the ISSN for the series as a whole, the two numbers should appear together, each with its own prefix. The ISSN should be printed right after the title of the series, both in books and in advertising pieces.
It is appropriate for both ISBN and ISSN to be assigned to certain other types of publications, most notably annuals and other directories or reference publications. The ISBN identifies the particular year or edition, the ISSN identifies the ongoing serial.
ISSN should appear on publisher's advertisements (both direct mail and space adds) and catalogs, on the serials themselves, and in all other places where details of books and serials normally appear.
Changes Affecting ISSN
Serials often undergo changes, many of which result in a change of title. When this occurs a new ISSN must be assigned. The earlier ISSN is not discarded, however, because it is a permanent attribute of the serial when it was issued under the earlier title. To avoid printing an incorrect ISSN, publishers must notify the U.S. ISSN Center in advance of a pending title change--especially one affecting the cover title (which is often the source for the key title). The notification will be treated as a request for a new ISSN and the procedure is the same as that for the original ISSN request. Other changes to a serial such as those of imprint and frequency do not affect the ISSN assignment.
Display and careful use of the ISSN will help in the world-wide effort to make the number achieve its intended role as a valuable means of identifying serials.
Last Updated: August 7, 2015