Direct comparison
ISSN vs. eISSN: What's the Difference?
ISSN is a print edition's identifier; eISSN is the online edition's own distinct 8-digit code — not a format variant of one number.
Written and maintained by CASRAI Editorial Board
Last updated
Ask CASRAI · free to try
Ask about ISSN vs. eISSN: What's the Difference?
Ask your first 2 questions free below. Subscribers get 150 a day for $29 a month.
An AI assistant specialized in research administration. It cites the sources behind every answer, labels web answers and says when it can't answer.
Answers draw on CASRAI's guides and dictionary plus the federal and funder documents we index: Federal Register, Grants.gov, Regulations.gov and UKRI.
Works on this site and inside Claude, Cursor and the AI tools you already use.
Everything CASRAI publishes — this page, the dictionary, the guides and the news — stays free to read, with no account and no card.
How do ISSN (Print), eISSN (Online) compare side by side?
The table below compares ISSN (Print), eISSN (Online) across 8 procurement-relevant dimensions, from what it identifies through implies peer review or quality?.
Side-by-side comparison
| Dimension | ISSN (Print) | eISSN (Online) |
|---|---|---|
| What it identifies | The print edition of a continuing serial title | The online/electronic edition of the same serial title |
| Governing standard | ISO 3297 | ISO 3297 (same standard, separate registration) |
| Format | 8 digits, NNNN-NNNC, modulus-11 check digit | 8 digits, NNNN-NNNC, modulus-11 check digit — same format, different digits |
| Assigned by | National ISSN Centre (or ISSN International Centre / CIEPS directly) | Same assigning body, as a separate registration for the online medium |
| Same code as its counterpart? | No — a distinct code from the eISSN | No — a distinct code from the print ISSN |
| If only one edition exists | Print-only title: only an ISSN is registered | Online-only title: only an eISSN is registered, and it typically also serves as the ISSN-L |
| Linking mechanism | Conventionally designated the ISSN-L when a print edition exists | Not usually the ISSN-L when a print counterpart exists, but can be if the title is online-only |
| Implies peer review or quality? | No | No |
Common questions
Common questions about ISSN (Print) vs eISSN (Online)
Is eISSN just the ISSN written differently for online use?
+
No. eISSN is a separate, independently assigned eight-digit code — not a reformatted version of the print ISSN. A title published in both editions genuinely has two different numbers.
Can a journal have an eISSN but no print ISSN?
+
Yes. An online-only journal is registered once, for the online medium, and that single eISSN typically also functions as the title's ISSN-L since there's no print edition to link to.
Which number should I cite, ISSN or eISSN?
+
Cite whichever matches the edition you used if a style requires it specifically; use the ISSN-L when a single number needs to represent the title regardless of format.
Do ISSN and eISSN ever end up as the same digits?
+
No — they're assigned independently and there's no mechanism that produces a matching pair by design; an apparent match would be a data error worth reporting.
Going deeper
