Most “Zotero vs Mendeley” comparisons list the same twenty features side by side and leave you exactly where you started. The two tools overlap almost completely on the basics — both collect references from your browser, store PDFs, insert citations into a word processor, and format a bibliography in whatever style your journal demands.
So the choice is not really about features. It comes down to four things that actually differ, and that are expensive to change your mind about later.
1. Who owns the tool, and does that matter to you
Zotero is developed by the Corporation for Digital Scholarship, a non-profit. It is open source, and the data format is documented. If the organisation disappeared tomorrow, your library would still be a readable SQLite database on your own disk.
Mendeley is owned by Elsevier, one of the largest academic publishers. In practice this rarely affects day-to-day work. It matters if you have a position on publisher consolidation, if your institution has taken one, or if you remember Mendeley Desktop being pulled from download in September 2022 to move everyone onto Mendeley Reference Manager — a call Elsevier later softened, saying in 2025 that Desktop is “here to stay” but will get maintenance only and no new feature development. That is the kind of decision worth weighing when it lands mid-project.
This is a values question rather than a technical one, and it is worth answering first, because it makes the rest of the comparison shorter.
2. Storage: the free tiers are not comparable
Free storage is where people hit a wall about eighteen months in.
- Zotero gives 300 MB free. That is roughly 100–200 PDFs depending on your field. Paid tiers go up from there.
- Mendeley gives 2 GB free — noticeably more headroom before you have to decide anything.
There is an important nuance on the Zotero side: you can keep your metadata synced through Zotero’s servers while storing the PDFs themselves somewhere else — a university file share, or a folder your own cloud storage syncs. Community plugins exist specifically to manage this. So Zotero’s 300 MB is a softer limit than it looks, at the cost of a bit of setup.
If you never want to think about storage plumbing, Mendeley’s free tier is simply larger.
3. Extensibility, and the LaTeX question
This is the sharpest practical difference.
Zotero has a real plugin ecosystem. The one that decides the matter for many people
is Better BibTeX, which gives you stable, human-readable citation keys
(smith2024attention, in a format you define yourself) and keeps a .bib file
continuously in sync with your library. If you write in LaTeX, that combination is
close to the default workflow in several fields.
Mendeley has no comparable plugin ecosystem. Mendeley Reference Manager can export
BibTeX, but the export is a one-off file: there is no setting to keep a .bib
continuously in sync with your library, and the citation keys it generates follow a
fixed author-year pattern rather than one you define. (The old Mendeley Desktop did
have a BibTeX sync option, but it now gets maintenance only.) And you cannot extend
the tool when your workflow needs something slightly different.
The rule of thumb:
- You write in LaTeX or Overleaf → Zotero plus Better BibTeX, almost without argument.
- You write in Word and want it to just work → either is fine; Mendeley Cite is clean and well maintained.
4. Collaboration and group libraries
Both support shared libraries, with different shapes:
- Zotero puts no limit on how many members can join a group. Files stored in a group draw on the group owner’s storage quota, and public open-membership groups cannot store files at all — so a large shared library needs someone to hold a paid plan.
- Mendeley allows private groups on the free tier, but with limits: 5 groups of up to 25 members each, sharing 100 MB of storage between them.
For a two-person paper, both work. For a lab-wide shared library, work out whose quota is paying for it before you standardise on one.
A short version
| If you… | Choose |
|---|---|
| Write in LaTeX | Zotero + Better BibTeX |
| Want the largest free storage with no setup | Mendeley |
| Care that the tool is open source and non-profit | Zotero |
| Want to extend or script your workflow | Zotero |
| Want a polished Word add-in and little else | Either |
The job neither of them does
Here is the thing both tools have in common, and it is the reason many researchers end up running something alongside one of them.
Zotero and Mendeley are libraries. They are excellent at holding papers you have already found, and at turning them into a correctly formatted bibliography. Neither is built to help you find the next paper. When you have one important paper and need to know what it built on and who has built on it since, both tools are silent — you go back to a search engine and start again.
That gap is where citation-graph tools sit. Litlas is one of them: you search across multiple sources, open the citation graph around a paper to walk backwards through its references and forwards through its citations, and save what matters into a library with your own notes attached. It imports and exports BibTeX and RIS, so it sits next to Zotero or Mendeley rather than demanding that you migrate, and it formats citations in APA, Chicago (author-date), IEEE, MLA and Vancouver.
To be clear about what it is not: Litlas has no Word plugin, and it is not a systematic-review platform — there is no screening workflow or PRISMA diagram. If your requirement is “cite while I write in Word”, Zotero and Mendeley both do that and Litlas does not.
How to decide in ten minutes
- Answer the ownership question. If open source matters to you, the answer is Zotero and you can stop.
- Check whether you write in LaTeX. If yes, Zotero plus Better BibTeX.
- If neither applies, install both, import the same twenty papers into each, and write one paragraph with citations in each. The one that annoys you less is the right answer; the differences that remain are genuinely small.
- Separately, ask whether your real problem is managing papers or finding them. If it is finding them, a reference manager of either brand will not fix it.