Paper Finder
Paste DOIs or paper titles — one per line — and find legal, free open-access copies in seconds.
Your references
Results
Results will appear here
Add references on the left, then click Find papers.
Paper Finder locates open-access copies that publishers and authors have made legally available. Availability depends on each paper - when no free version exists, please access the paper through your library or the publisher.
What this searches, and why it is legal
Paste a DOI or a paper title and this looks for a copy the authors or publishers have already made freely available. It queries Crossref to resolve what the paper actually is, then Unpaywall to find open-access locations for it.
Every result is a copy that is legitimately free to read. That is the whole design: it does not host anything, does not bypass paywalls, and does not touch the shadow-library sites that circulate pirated PDFs. It points at the publisher's own open-access version, an institutional repository, a funder repository like PubMed Central, or a preprint server.
That distinction matters practically as well as legally. Repository copies are permanent, citable, and safe to link in a reading list. A file from a piracy site is none of those things.
Why a free copy so often exists
A surprising proportion of paywalled papers have a legal free version somewhere, for reasons that have nothing to do with the publisher being generous:
- Funder mandates. Most major research funders now require that work they paid for be deposited in an open repository, often within twelve months of publication.
- Green open access. Many publishers permit authors to self-archive the accepted manuscript - the peer-reviewed text before the publisher's typesetting - in their institution's repository.
- Preprints. In physics, maths, computer science, biology and increasingly elsewhere, authors post the paper before submission. The science is the same even when the pagination is not.
- Hybrid and fully open journals, where an article processing charge has already bought public access to that specific article.
When nothing comes back
A blank result usually means one of three things, and they call for different responses.
The identifier did not resolve. Titles are matched loosely, so a slightly wrong title or a missing subtitle can miss. A DOI is exact and always the better input if you have one - it is the string beginning "10." on the article page.
The paper is genuinely closed. Older work in particular predates deposit mandates entirely. Emailing the corresponding author is unglamorous and works far more often than people expect; authors are generally pleased that someone wants to read their paper.
It exists but is not indexed. Unpaywall is very good and not exhaustive. Checking the author's personal page, their institutional repository, or their lab site is worth two minutes before giving up.
If your institution has a library subscription, that remains the fastest route for closed material, and interlibrary loan exists precisely for the rest.
Common questions
Is this legal?
Yes. It only surfaces copies that publishers, authors or repositories have already made openly available - publisher open access, institutional and funder repositories, and preprint servers. It hosts nothing and links to no piracy sites.
What should I paste in?
A DOI is best because it identifies the paper exactly. Titles work but are matched loosely, so an inexact or truncated title can miss. You can paste several, one per line.
Why did it find nothing for my paper?
Either the title did not match, or no open copy has been deposited - common for older papers published before open-access mandates. Try the DOI instead, then check the author's own page or email them directly.
Is a preprint the same as the published paper?
Not identical. A preprint is the version before peer review, and an accepted manuscript is the peer-reviewed text before the publisher's formatting. The science is usually the same, but page and section numbers may differ, so cite the version you actually read.
Where do the results come from?
Crossref resolves the identifier and metadata; Unpaywall supplies the open-access locations. Both are established scholarly infrastructure rather than scraped indexes.
Related tools
- Citation Generator - turn the DOI you just looked up into a formatted reference.
- AI Detector - built for academic writing, with sentence-level highlights.
- How to find a free, legal PDF - the manual version, in the order that works fastest.