What Is an ISSN? Clear, Beginner-Friendly Explanation and Examples

For someone encountering the term ISSN for the first time, the simplest description is: an ISSN is a unique identifier for serial publications. But there’s more to it than a code—ISSNs solve practical problems in cataloguing, discovery, subscription management, and citation. This article explains what an ISSN is, how it is formatted, the different types of ISSNs, and practical examples of how they are used.

Basic definition

ISSN stands for International Standard Serial Number. It is an eight-character code used internationally to identify serials—publications that are released in successive parts and intended to continue indefinitely. Examples include academic journals, monthly magazines, weekly newspapers, continuing reference resources, and some ongoing digital series.

ISSN format and check digit

An ISSN has eight digits usually displayed as two groups of four separated by a hyphen: XXXX-XXXX. The final digit is a check digit that may be 0–9 or the letter X (which represents the value 10). The check digit helps verify that an ISSN has been recorded or transmitted correctly. For example, an ISSN might look like 1234-5679 or 2049-363X.

Print ISSN vs Electronic ISSN

A serial published in more than one medium often receives separate ISSNs for each medium: a print ISSN (p-ISSN) for the physical edition and an electronic ISSN (e-ISSN) for the online edition. This distinction helps libraries, subscription agents, and platforms manage holdings and access. Some publishers display both ISSNs in the publication’s masthead or on the website.

ISSN-L (linking ISSN)

ISSN-L is a concept introduced to group all media versions of the same serial title under a single linking ISSN. ISSN-L helps systems aggregate different manifestations (print, electronic, CD-ROM, etc.) of a serial to make metadata exchange and discovery simpler. Usually, the ISSN-L corresponds to the ISSN of the first published medium of the serial.

How ISSN differs from ISBN

ISSN identifies serial publications that continue over time; ISBN (International Standard Book Number) identifies monographs (books) and their specific editions. A book series or multi-volume set might have both ISBNs (for individual volumes) and an ISSN (for the series as a whole), so it’s important not to confuse the two systems.

Purposes and practical uses

• Cataloguing: Libraries use ISSNs as stable identifiers in catalog records and discovery systems.
• Subscription management: Vendors and subscription agents use ISSNs to order and manage serials.
• Indexing and abstracting: Databases use ISSNs to accurately link article records to the correct journal.
• DOI and metadata: CrossRef and other metadata services use ISSNs as part of their serial-level metadata.
• Legal deposit and preservation: ISSNs help national libraries and archives track and preserve serial publications.

Examples

• A monthly news magazine might have a print ISSN 0140-6736 and an eISSN 1474-547X.
• An academic journal’s publisher lists the print ISSN and eISSN in the article PDF and on the journal homepage to make it easy for libraries and databases to identify and link it.

How ISSNs are assigned

ISSNs are assigned by national or regional ISSN centres, coordinated by the ISSN International Centre. Publishers apply to the appropriate centre, providing title information, frequency, publisher name, and a sample issue or URL for an electronic serial. Once verified, the centre issues the ISSN and the title is added to the international ISSN Register.

When to use an ISSN in practice

Include ISSNs in metadata, mastheads, article citations, library records, and subscription listings. If you are publishing a serial, display the ISSN prominently to help distributors and readers find and cite your title correctly.

Common beginner questions

• Can I make an ISSN myself? No. ISSNs must be issued by an authorized ISSN centre.
• Does every issue of a journal have a different ISSN? No. An ISSN identifies the serial title, not individual issues. Individual articles may have DOIs; issues are usually identified by volume and issue numbers together with the ISSN.
• Is an ISSN required? Not mandatory, but highly recommended for discoverability, indexing, and subscription management.

Summary

An ISSN is a simple but powerful international identifier that makes managing and discovering serial publications easier. Whether you are a publisher, librarian, researcher, or reader, understanding what an ISSN is—and how to use it—improves the accuracy and efficiency of handling serial content.