TL;DR

• An ISSN is a unique 8-digit code that identifies a serial publication.

• Every legitimate peer-reviewed journal has at least one ISSN.

• Checking for an ISSN helps you spot credible journals from predatory ones.

• ISSNs are assigned by a global network of national ISSN centres.

• Your paper gets a DOI, not an ISSN — the journal holds the ISSN.

You have finished your research paper. Now you need to find the right journal to submit it to. You look up a few options and notice a string of numbers on each journal's website, often written as ISSN 1234-5678. Nobody explained what that number means or why it is there.

That confusion is common. Most guides to academic publishing skip over the basics and jump straight into submission portals and cover letters. But understanding what an ISSN is, and how to use it, gives you a fast and reliable way to check whether a journal is legitimate before you invest weeks of work submitting to it.

This post explains exactly what an ISSN is, how the system works, and how you can use it practically as a student researcher.

What Is an ISSN?

An ISSN, or International Standard Serial Number, is an 8-digit code used to uniquely identify a serial publication. A serial publication is anything published in ongoing issues or volumes, including academic journals, magazines, and newspapers. Every ISSN is formatted as two groups of four digits separated by a hyphen, for example: ISSN 2049-3630. The final digit is a check digit used to verify the number is valid.

The ISSN system is governed by ISO 3297, an international standard maintained by the ISSN International Centre, which is based in Paris and operates under the auspices of UNESCO. According to the ISSN International Centre, there are currently more than 2.3 million ISSNs registered in the global ISSN Portal. Each one points to a specific publication, not a specific article and not a specific author.

If you have come across a DOI before and are wondering how it differs, the distinction is straightforward. A DOI, or Digital Object Identifier, is assigned to an individual article or document. An ISSN is assigned to the journal itself. You can read more about how DOIs work and why your published paper will need one in this guide to what a DOI is and why your paper needs one.

Why Does a Journal Have an ISSN?

A journal holds an ISSN so that libraries, databases, and researchers around the world can identify it without ambiguity. Journal names can be similar or even identical across different publishers and countries. The ISSN removes that ambiguity entirely. Two journals with the same name will have different ISSNs, and that difference is what allows indexing databases like Scopus, PubMed, and the Directory of Open Access Journals (DOAJ) to track them separately.

When a journal changes its title, it receives a new ISSN. The old ISSN is not deleted. It is linked to the new one so the publication history stays intact. This matters for researchers tracing citations across decades of literature.

Print and online versions of the same journal can also have different ISSNs. The print version carries a p-ISSN and the online version carries an e-ISSN. Many journals today are online-only and therefore have only an e-ISSN. Both formats are equally valid.

How to Use an ISSN to Check If a Journal Is Legitimate

One of the most practical uses of an ISSN for a student researcher is verification. Predatory journals, which are publications that charge fees without providing genuine peer review, often list fake or borrowed ISSNs on their websites. Checking the ISSN directly is one of the fastest ways to catch this.

Here is how to verify a journal's ISSN in three steps:

1. Find the ISSN listed on the journal's website, usually in the footer, the about page, or near the submission guidelines.

2. Go to the ISSN Portal at portal.issn.org and enter the number in the search field. The portal is free to search.

3. Check that the journal name, publisher, and country in the portal record match what the journal claims on its own website. A mismatch is a warning sign.

Having an ISSN does not automatically mean a journal is reputable. The ISSN system is a registration system, not a quality certification. A predatory journal can legally obtain an ISSN. But cross-referencing the ISSN with a trusted index like DOAJ or Scopus gives you a much clearer picture. If a journal has a valid ISSN and also appears in DOAJ, that combination is a meaningful positive signal.

If you are working through the broader question of which journals are worth submitting to, understanding what an impact factor means for student researchers will help you build a fuller picture of journal quality.

What Is an ISSN for Open Access Journals Specifically?

Open access journals use ISSNs in exactly the same way as subscription journals. The ISSN system does not distinguish between access models. A fully open access journal, a hybrid journal, and a paywalled journal all receive ISSNs through the same process via their national ISSN centre.

Where the ISSN becomes especially useful for open access research is in the DOAJ. The DOAJ, which is the Directory of Open Access Journals, uses ISSNs as primary identifiers in its database. If you search for a journal in DOAJ by its ISSN and find a confirmed record, you can be confident the journal meets DOAJ's criteria for legitimate open access publishing. Those criteria include a genuine editorial process and transparent publishing policies.

Open access publishing raises its own set of questions for student researchers, particularly around article processing charges and copyright. If you want to understand those trade-offs before choosing where to submit, this overview of what open access publishing is and whether you should care covers the key points clearly.

If you are still building your paper and want structured feedback before you reach the submission stage, joining the Publication Compass waitlist gives you early access to an AI platform designed to help student researchers go from draft to submission-ready.

What Is an ISSN Compared to Other Journal Identifiers?

The ISSN is not the only number you will encounter when researching journals. Here is how the main identifiers differ:

1. ISSN: Identifies the journal as a whole publication. Assigned once, stays with the journal. Managed by the ISSN International Centre.

2. DOI: Identifies an individual article. Assigned at the article level by a registration agency such as Crossref. Persistent and clickable as a URL.

3. NLM ID: A numeric identifier used by the National Library of Medicine to track journals indexed in PubMed. Relevant primarily for biomedical research.

4. Scopus Source ID: An internal identifier used by the Scopus database. Not universal, only applies to journals indexed there.

As a student submitting your first paper, the ISSN and the DOI are the two identifiers you will encounter most often. The ISSN tells you which journal you are dealing with. The DOI is what your published article will carry once it is live.

How Does a Journal Get an ISSN?

A journal publisher applies for an ISSN through the national ISSN centre in their country. There are 89 national centres worldwide, each responsible for registering publications from their territory. If no national centre exists in a given country, the ISSN International Centre in Paris handles the registration directly.

The process is straightforward. The publisher submits basic information about the publication, including its title, subject area, frequency, and publisher details. The national centre reviews the application and assigns the ISSN. Registration is free in most countries, though some national centres charge a small administrative fee.

Once assigned, the ISSN is permanent. It does not expire and does not need to be renewed. This permanence is part of what makes the system reliable for long-term citation tracking.

Understanding how journals are structured and governed also helps you understand what peer review actually involves once your paper is submitted. This explanation of what peer review is and what happens to your paper walks through the full process from submission to decision.

Does Your Research Paper Need an ISSN?

No. Individual research papers do not receive ISSNs. The ISSN belongs to the journal, not to the content published inside it. Your paper will receive a DOI once it is published, and that DOI is how other researchers will cite and locate your specific article.

If you are publishing a preprint, meaning an early version of your paper uploaded to a repository before formal peer review, the preprint server itself has an ISSN. Your individual preprint will receive its own DOI from the repository. Understanding the difference between a preprint and a formally published article matters before you decide how to share your work. This guide on what a preprint is and whether you should upload before submitting explains the trade-offs.

Publication Compass is a platform that helps student researchers identify the right peer-reviewed journals for their work, receive structured feedback on their drafts, and navigate the submission process step by step. It does not assign ISSNs and is not a journal. It is a tool for getting your paper to the journals that are right for it.

Frequently Asked Questions

What is an ISSN number used for?

An ISSN, or International Standard Serial Number, is used to uniquely identify a serial publication such as an academic journal. Libraries, databases, and publishers use ISSNs to track and distinguish journals, especially when titles are similar. Researchers use them to verify that a journal is registered and to locate it in indexing databases.

Does every journal have an ISSN?

Every legitimate, registered journal should have at least one ISSN. Online journals carry an e-ISSN. Print journals carry a p-ISSN. Many journals have both. If a journal claims to be peer-reviewed but has no ISSN listed, or if the ISSN cannot be verified in the ISSN Portal, treat that as a warning sign worth investigating further.

Can a fake or predatory journal have an ISSN?

Yes. Obtaining an ISSN does not require a journal to meet any quality standard. It is a registration, not an endorsement. Predatory journals can and do register ISSNs. To assess journal legitimacy, cross-check the ISSN against trusted databases such as DOAJ or Scopus in addition to verifying the number itself.

What is the difference between an ISSN and a DOI?

An ISSN identifies a journal as a whole publication. A DOI identifies a single article or document within that journal. When your paper is published, it receives a DOI. The journal it is published in has an ISSN. Both identifiers are permanent and globally recognised, but they operate at different levels.

Where can I look up an ISSN?

The official place to look up any ISSN is the ISSN Portal at portal.issn.org, maintained by the ISSN International Centre. The search function is free to use. You can search by journal title or by the ISSN number itself. The portal returns the registered title, publisher, country, and format details for any valid entry.

Conclusion

An ISSN is a small detail that carries real weight. It tells you a journal is registered, helps you verify its identity, and connects it to the global infrastructure of academic publishing. For a student submitting research for the first time, knowing how to read and check an ISSN is one of the simplest ways to protect your time and make sure your work goes somewhere credible.

The next step is finding the journals that are the right fit for your specific research. That means understanding scope, submission requirements, and what editors are actually looking for. You can find practical guidance on all of that across the Publication Compass blog.