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DOI to Citation Generator

Paste DOIs, one per line or a whole list, and each becomes a full citation in APA 7th edition, MLA 9th, Harvard, Chicago, Vancouver or IEEE.

  • Free, no sign-up, no limits
  • Checks 5 free scholarly databases
  • Nothing stored by LetRelay

Word (.docx), .bib, .ris and .txt files work. Each reference is looked up in free public databases; nothing is stored by LetRelay.

How to use it

  1. Paste your DOIs

    One per line, in any form: 10.1038/nature14539, https://doi.org/..., or doi:...

  2. Check what came back

    Each DOI shows its paper. One that does not exist, or a retracted paper, is flagged.

  3. Copy the citations

    Choose APA, Harvard, Vancouver, IEEE, Chicago or MLA, then copy or download Word, BibTeX or RIS.

The details come straight from the publisher's record in Crossref or DataCite, a DOI that does not exist is pointed out, and a retracted paper is flagged before it reaches your reference list.

Straight from the publisher's record

A DOI is registered by the publisher with the work's details, so a citation made from it is as accurate as the publisher's own record. Each DOI is read from Crossref (journals, books, conference papers) or DataCite (arXiv, Zenodo and repositories). If neither has it, doi.org says whether the DOI exists at all: one that does not exist usually has a typo, or was invented by an AI tool.

How each reference is checked

Most reference checkers either only look at punctuation, or send your list to an AI that can itself make things up. This one looks every reference up in the published record, and only calls it found when a record agrees on both the title and the authors. The databases, all free and public, are asked in this order, cheapest and most exact first:

DatabaseWhat it holdsUsed for
doi.orgEvery DOI ever registered, with any agencyDoes the DOI in your reference exist at all?
Crossref188 million records: journal articles, books, chapters and conference papers with a DOIThe DOI's own record, and matching the whole reference as written
Europe PMC49 million records, including all of PubMed and PubMed Central, and preprintsMedicine and life sciences, also papers without a DOI
DataCitearXiv, Zenodo, figshare, Dryad and university repositoriesPreprints, datasets and theses
Open LibraryBooks, with every edition and printingBooks that have no DOI
OpenAlex318 million works from all of the above and moreAnything the others missed, and retraction flags

When a record matches, the year, DOI, journal, volume and pages are compared with what you wrote. A different year is only called wrong when the journal, volume or pages confirm it is the same publication, and for books it is never called wrong, because editions and reprints carry their own years. Matched papers are checked for retractions with the Retraction Watch database (part of Crossref since 2023).

What the results mean

  • Verified: a published record agrees with the reference on title, authors and year. Nothing to change.
  • Found, with fixes: the work exists, but something in your reference is wrong (year, DOI, first author, journal, volume or pages). The correct value is shown next to yours, and the finished list uses it.
  • Retracted: the work exists but has been retracted, withdrawn or given an expression of concern. Do not rely on it.
  • Does not match: the title exists under other authors, or the DOI belongs to a different work. This is how AI-made references often look.
  • Check this one: a close record was found but something important differs. Open it and say yes or no.
  • Not found: no database has it. It may be invented, or a source they do not cover (an unpublished thesis, a report, a web page, a paper from the last few days). Search Google Scholar with one click before you keep it.

What it cannot do

No free database holds every source, so the tool never calls a reference fake: it says not found and tells you where to look. It cannot see whether a paper says what you cite it for; it proves the paper exists and is cited correctly, so read the part you rely on. Web pages, laws, standards and most reports are not in paper databases, so those are labelled rather than checked. Titles are put in sentence case for APA, Vancouver and IEEE; a program cannot always tell a name from an ordinary word, so check capitals in names of places, methods and software. Your own titles keep your capitals unless you ask otherwise.

How we tested it

Before release it was run against 56 references in APA, Harvard, Vancouver, IEEE, Chicago and MLA, from biology, medicine, psychology, economics, computer science and sociology: 40 real journal articles, conference papers, books, chapters and preprints; two well-known retracted papers; four real papers with one deliberate error each (a year, two DOIs, an author list); and ten references invented the way AI chatbots invent them. 38 of the 40 real works were found and verified. The other two: a WHO report, labelled as a report because paper databases do not list reports, and the 2014 conference paper that introduced GANs, which no free database lists under its published title (it came back “not found”, or “check this one” when OpenAlex was available, which is why not found never means fake). Both retractions were flagged, all four deliberate errors were caught, and none of the ten invented references was accepted. The formatting of every style was compared with the official CSL style files run by citeproc-js, the engine inside Zotero and Mendeley: 189 style and record pairs come out identical, and the rest differ only where we follow the style guide on purpose.

More free reference tools

The same engine, set up for a different job: Reference checker, Citation checker, AI citation checker, DOI to BibTeX converter, BibTeX to APA converter, APA to Vancouver converter, BibTeX to RIS converter and RIS to BibTeX converter. Writing a thesis? The dissertation word count breakdown splits your word limit by chapter, and the PhD Gantt chart maker plans the time.

Frequently asked questions

How do I turn a DOI into an APA citation?

Paste the DOI above and choose APA 7 (it is the default). The tool reads the publisher's record for that DOI from Crossref, or DataCite for arXiv and Zenodo DOIs, and writes the APA 7 reference with the authors, year, title, journal, volume, issue, pages and the DOI as https://doi.org/... .

Can I convert many DOIs at once?

Yes, up to 500 at a time. DOIs are quick: a list of 50 usually takes well under a minute.

What if a DOI does not work?

Each DOI that no database knows is checked with doi.org itself, which covers every registration agency. If doi.org has never heard of it, the DOI does not exist: it may have a typo, or it may be invented (AI tools often invent DOIs).

Which DOIs work?

Crossref DOIs (journals, books, chapters and conference papers from almost every publisher) and DataCite DOIs (arXiv preprints, Zenodo, figshare, Dryad and university repositories). A few other agencies, such as mEDRA, JaLC and CNKI, are confirmed by doi.org but their details are not in the free databases.

Which citation styles are there?

APA 7th edition, Harvard (Cite Them Right), Vancouver (NLM), IEEE, Chicago 18th edition (author-date) and MLA 9th edition, plus BibTeX and RIS files.

Is it free?

Yes. There is no sign-up, no daily limit, no watermark and no paid tier. The databases it asks are free public services, called straight from your browser, so checking costs LetRelay nothing and there is nothing to charge for.