Understanding ISSN Codes in Journals: A Complete Guide
When you skim the masthead of a research journal, you’ll notice a six‑digit number with a dash: that’s the ISSN. It’s short for International Standard Serial Number and is the serial’s fingerprint in the scholarly world. In this guide we’ll unpack what the ISSN is, why it matters, how to read it, and what authors and publishers need to know.
What Is an ISSN?
The ISSN is an eight‑digit code—formatted as four digits, a dash, then four more—that uniquely identifies a serial title, whether it’s a print journal, an online magazine, or a continuing periodical. The last digit is a check character that can be a number or the letter “X.” The system was launched in 1975 by the ISSN International Centre and has become the standard way libraries, databases, and publishers label serials.
Why Journals Need an ISSN
Serials can have similar titles, change names, or spin off new editions. The ISSN eliminates confusion by providing an immutable identifier. For libraries, it simplifies cataloging and inter‑library loans. For indexing services like Scopus or Web of Science, the ISSN ties metadata to the correct journal, ensuring accurate citation counts and impact metrics. Publishers use it to manage subscriptions, track sales, and comply with national regulations.
How to Find the ISSN
Every journal lists its ISSN in the masthead or on the first page of the PDF. In the digital realm, you can often spot it in the article’s doi.org metadata or on the journal’s homepage under “About.” When you search a database, filter results by ISSN for precision. If a journal has both print and online editions, each will have its own ISSN (see the next section).
ISSN vs ISBN
People sometimes mix up ISSNs with ISBNs. ISBNs—International Standard Book Numbers—apply to books, not serials. The formats differ: ISBNs are 10 or 13 digits, while ISSNs are always eight. A journal’s monograph or special issue might carry an ISBN, but the ongoing title remains tied to its ISSN.
Digital vs Print ISSN
Most journals now have two ISSNs:
- Print ISSN (pISSN) – assigned to the hard‑copy version.
- Electronic ISSN (eISSN) – assigned to the online version.
Both numbers can appear on the same PDF or website, but they serve different cataloging needs. When citing an online article, many style guides recommend including the eISSN, while print citations use the pISSN.
Practical Tips for Authors and Publishers
- Check the ISSN before submission: Some journals accept only manuscripts with the correct ISSN in the file name or metadata.
- Use the correct format: Always write the ISSN as four digits, a dash, four digits. Example:
1234-5678. - Verify the check digit: A quick arithmetic check (modulus 11) can confirm validity, preventing typos that could break indexing.
- List the ISSN in the reference: For example: Smith, J. (2024). “Title.” Journal Name, ISSN 1234-5678, 10(2), 45‑60.
- Update the ISSN when a title changes: Publishers must register the new title and obtain a fresh ISSN. The old ISSN remains for legacy issues.
Common Pitfalls and How to Avoid Them
1. Mixing up the print and electronic ISSNs: Always double‑check which edition you’re referencing. 2. Omitting the ISSN altogether: Many citation styles consider it optional, but including it strengthens traceability. 3. Using a 9‑digit or 10‑digit number: That would be an ISBN or a malformed ISSN; databases will reject it. 4. Not updating when a journal rebrands: Old ISSNs become orphaned, leading to citation fragmentation.
When in doubt, consult the journal’s official website or the ISSN Portal. It’s the definitive source for checking validity, retrieving the correct ISSN, and understanding the history of a title.
FAQ
Q: Can a journal have more than two ISSNs?
A: Yes. A journal with multiple formats—print, web, and PDF—might list separate ISSNs for each. Special issues or series can also carry distinct ISSNs.
Q: Is the ISSN needed for article PDFs?
A: It’s optional for readers but highly recommended for publishers and libraries because it ensures the PDF is correctly indexed and retrievable.
Q: How do I compute the check digit?
A: Multiply each of the first seven digits by weights 8 to 2, sum the results, divide by 11, and subtract the remainder from 11. If the result is 10, the check digit is “X.” If it’s 11, the digit is 0.
Q: What happens if I submit a paper with a wrong ISSN?
A: Many submission systems flag it. Even if accepted, indexing services may misclassify the article, affecting visibility and citation metrics.
