Free ISSN Checker

How the ISSN Checker works

1. We strip the dash and check that you have 8 characters (7 digits + 0-9 or X check digit).
2. The checksum is verified using the standard ISSN algorithm — sum of digit × weight (8..2), modulo 11.
3. If valid, we look up the journal in our catalog by ISSN or eISSN and show live indexing badges.
4. Predatory journals often display malformed ISSNs hoping nobody validates them — this is a strong red flag.

Why this matters

An ISSN with a valid checksum confirms the journal has a registered identifier with the ISSN International Centre — but it does not confirm the journal is reputable. Always check the indexing badges (Scopus / DOAJ / OpenAlex / UGC CARE) for that. UGC CARE Group II accepts journals indexed in Scopus or Web of Science.

Worked examples

Three ISSNs and what the result panel shows for each:

• 0028-0836 (Nature, print ISSN) — checksum passes. The panel confirms the journal, shows the publisher and founding year, and lights up green Scopus, DOAJ-where-applicable, OpenAlex and Web of Science badges. A link to the full journal profile lets you compare its APC and quartile.
• 2167-8359 (PeerJ) — a born-digital open-access journal. The checksum validates and the panel flags it Open Access with its article-processing charge, plus indexing badges that reassure you it is a legitimate OA venue rather than a predatory clone.
• 1234-5679 — a deliberately malformed example. The final digit fails the mod-11 checksum, so the panel rejects it as not a real ISSN before any catalog lookup runs. This is exactly the kind of fake identifier a predatory publisher might print on its site.

What this tool checks and why it matters

An ISSN (International Standard Serial Number) identifies a journal as a serial publication. The eighth character is a check digit mathematically derived from the first seven, so a single mistyped digit makes the whole number invalid. This tool first verifies that checksum — a cheap, instant test that catches typos and outright fabrications. It then does the part that actually protects you: it looks the journal up and surfaces real Scopus, DOAJ, OpenAlex/Web of Science and UGC CARE indexing. That second step matters because a valid ISSN proves only that an identifier was registered, not that the journal is reputable. Predatory publishers routinely display ISSNs — sometimes valid, sometimes fabricated — alongside invented metrics. Confirming both a clean checksum and genuine indexing is the fastest way to vet a journal before you pay an APC or submit a manuscript.

Common error cases

• Wrong length — an ISSN is exactly 8 characters. Pasting a DOI, an ISBN (13 digits), or a truncated number fails immediately.
• Lower-case or missing X — the check digit can be the letter X (meaning 10). We accept upper or lower case, but a missing final character fails.
• Valid checksum, journal not in catalog — the format is correct but we have no record yet. You can suggest the journal and we verify it within 48 hours.
• Confusing print ISSN with eISSN — many journals have two ISSNs. Either resolves here; the panel labels which one matched.

Frequently asked questions

Related tools

• DOI Checker — for article-level lookups
• ORCID Checker — for author-level lookups
• Indexing Tracker — full Scopus / DOAJ / WoS / UGC CARE coverage dashboard