Citation Checker — do your sources really exist?
Free · Thesis & dissertation

Citation checker: Do your citations really exist?

ChatGPT invents references that look perfect and lead nowhere. Before you submit, check that every source is real and find the claims you left without one. Two minutes, free.

Check my text →
Crossref · real DOI lookupPrivate · analysed in your browser
verifiednot confirmednot found
Piketty, T. (2013)
Found on Crossref · valid DOI
Dupont (2020), p.44
Not confirmed — check the reference
“78% of students…”
Claim with no source
The tool

Check your citations and sources

No generative AI involved: this is a factual lookup through Crossref.

NOT an AI detectorSources verifiedTraceabilityHuman review optional
How it works

Three steps, no sign-up

1

Paste your text

Up to 1,500 words, or drop a PDF, DOCX, ODT or TXT file. Nothing leaves your browser.

2

We check it

Every citation goes to Crossref; claims without a source are flagged and located in your text.

3

Your report

Verified, not confirmed or not found, plus an AI-disclosure draft you can adapt.

Citation styles

An APA and MLA citation checker that verifies existence, not commas

A style guide tells you where the italics go. It cannot tell you whether the work exists. Below is exactly what happens to an APA, MLA, Chicago, Harvard, Vancouver or IEEE entry when you run it here.

What this tool never does: rewrite your entries. Commas, italics, ampersands and the order of the fields come back exactly as you typed them. Formatting is a style guide's job. What you get instead is whether the work behind each entry is real, and whether the year and title match the published record.

APA (7th edition)

In text(Piketty, 2013)
Reference listPiketty, T. (2013). Le capital au XXIe siècle. Seuil.

Both checks run. Every entry goes to Crossref, and a citation you used in the text but forgot to list is flagged as an orphan. That is the part an APA citation checker can give you and a style guide cannot: whether the work is real.

MLA (9th edition)

In text(Piketty 42)
Works CitedPiketty, Thomas. Capital in the Twenty-First Century. Harvard UP, 2014.

Your Works Cited heading is recognised, so every entry under it is verified. MLA in-text citations carry a page number rather than a year, so the orphan check cannot run on them. If you came looking for an MLA citation checker online, this is the half a formatter cannot do for you.

Harvard

In text(Piketty, 2013)
Reference listPiketty, T. 2013. Capital in the Twenty-First Century. Cambridge: Harvard UP.

Author–date, like APA, so both checks run and no heading is strictly needed.

Chicago

Author–date, in text(Piketty 2013)
Notes–bibliographyPiketty, Thomas. Capital in the Twenty-First Century. Cambridge, MA: Harvard University Press, 2014.

Author–date behaves like APA. In the notes system the footnote markers are not read, but every entry under your Bibliography heading is still verified.

Vancouver

In text… as reported previously [1].
References1. Piketty T. Capital in the Twenty-First Century. Cambridge: Harvard UP; 2014.

Numeric markers carry no author or year, so they are not read as citations. Add a References heading and every numbered entry below it is checked.

IEEE

In text… has been shown in [1].
References[1] T. Piketty, Capital in the Twenty-First Century. Cambridge, MA: Harvard UP, 2014.

Same as Vancouver: bracketed numbers are not citations to us, but the numbered list is verified once it sits under a heading.

One line that makes every style work

Put References, Works Cited, Bibliography or Sources on a line of its own above your list. With that heading, everything below it is treated as entries and checked whatever the style, including numbered Vancouver and IEEE lists, which are otherwise hard to tell apart from ordinary paragraphs. Without it, the tool falls back on the shape of an author–date entry, which is why APA, MLA, Chicago and Harvard lists are still picked up on their own.

Want to go further?

The proofreading tool reads a whole chapter against your university's rubric and hands you a prioritised list of fixes, with the option of a human expert.

Proofreading tool · €19 →
FAQ

Common questions

Important: this is NOT an AI detector and gives no “AI probability”. It checks whether your sources exist and whether your claims are traceable. No grade is guaranteed.
How do you check my citations?

Every DOI and reference line is looked up in the Crossref database, which indexes over 150 million scholarly records. If the source exists, it is marked “verified”; if not, “not confirmed”, which is not the same as “false”. In-text citations are matched against your own reference list, so a citation you forgot to list is flagged too.

Is this an APA or MLA citation checker?

Not in the formatting sense, and we would rather say so plainly. We do not correct commas, italics or the order of fields in an APA or MLA entry. We check something a formatter cannot: whether the work behind the entry actually exists, and whether the year and title match the record. Use a style guide for the punctuation, and this tool to make sure the reference is real.

Do you keep my text?

No. Everything runs in your browser: your file is uploaded to no server. Only the reference strings are sent to Crossref for lookup, and nothing remains once you close the tab.

Why does a reference come back “not confirmed”?

Usually because it is a book, a thesis or a report that Crossref does not index, or because the title in your list differs from the published one. It is a signal to check by hand, not a verdict.

Can a human read my work?

Yes. Our experts can take over through the proofreading tool, and for the whole document through the main service.

Do AI chatbots really invent references?

Yes, routinely. A language model produces references that look right — a plausible author, a real journal, a consistent year — but that match no published article. That is exactly what this checker looks for: every DOI and every reference is matched against Crossref, and anything not found there is flagged.

How do I check a DOI quickly?

Paste your bibliography. Each DOI is queried against Crossref and the tool shows the title actually registered behind that identifier. A valid DOI pointing at a different article than the one you cite is the most common case, and the hardest to spot by eye.

Does the tool fix my APA or MLA formatting?

No, deliberately. We do not move commas around in an APA or MLA entry. We check that the cited work exists and that your claims are attached to a source. Formatting stays with you or with your reference manager.

Other tools

Keep going

Updated on · Published by ProRédaction