FREEDocument AI Detector · no signup to start

AI detector for PDF and documents

Upload a PDF, Word (DOCX) or TXT file and get a score for the whole document — plus a page-by-page map on PDFs — built for students checking a paper before they submit it, and teachers checking whole assignments at once.

Per-page map on PDFsPDF · DOCX · TXTNo signupFiles aren't saved
Document Detector
Per-page AI score · highlights

Drop a DOCX or PDF

Free: first 1,500 words scored, up to 5 pages mapped. The document is sent securely over HTTPS to the TextSight API and processed on our servers.

Chrome extension New Check documents from your browser PDF, DOCX or TXT in Chrome. Free: 3 a day. Add to Chrome, free
How a check works
  1. UploadA PDF, Word (.docx) or .txt file, up to 25 MB. Scanned image-only PDFs have no text to read.
  2. We read and score itThe text is pulled out and scored by our AI detector. Free scores the first 1,500 words.
  3. See the resultAn overall AI score, plus a page-by-page map on PDFs (up to 5 pages free).

Files aren't saved. The document is sent over HTTPS, scored, and not stored.

RESULT
IDLE

No document checked yet

Upload a DOCX or PDF, or try the example, to get per-page AI scores.

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WHY TEXTSIGHT

Check the whole document, not just a paragraph

Per-page scores

See which pages read as AI-generated, not just an overall number — ideal for long assignments.

Every page scored separately

Each page goes through the detector on its own, so a spike on page 7 doesn't get averaged away.

Longer documents

Without an account the score reads the first 1,500 words; a free account reads up to 25,000. The page map covers the first 5 pages.

DOCUMENT-LEVEL AI DETECTION

Why a whole document needs more than a paragraph check

Most AI checkers expect you to paste in a block of text. That works for a single answer, but it falls apart the moment you're holding a 12-page essay, a 40-page report or a chapter draft. You end up copying sections one at a time, losing track of which slice came from where, and missing the part that actually matters: where in the document the writing shifts from a person's voice to a model's.

The Document AI Detector takes the whole file at once. It extracts the text from your PDF, keeps the page boundaries intact, and scores each page on its own — so instead of one flat number for the entire submission, you get a map. A clean opening followed by three suspiciously uniform middle pages tells you far more than a single average ever could, and it points you straight to the passages worth a closer human read. Without an account the document score is read from the first 1,500 words, and the result says so rather than presenting a partial read as a verdict on the whole file.

UNDER THE HOOD

From file to per-page score

When you drop in a file, it's sent securely over HTTPS to the TextSight API. The first job is extraction: pulling the readable text out of the document while preserving where each page starts and ends. PDFs with a real text layer come through cleanly, page boundaries and all. DOCX and TXT files are read as one continuous document — neither format has fixed pages, so those get a document score without a page map. Scanned, image-only PDFs have no selectable text to extract, and this tool doesn't OCR them.

From there, the same language model that powers our core detector runs across the extracted text. It weighs the statistical patterns that tend to separate machine-written prose from human writing — how predictable each word is given the ones before it, how evenly sentences are paced, and how little the rhythm varies from line to line. Human drafts are messier: they wander, hedge, repeat a favourite phrase, and break their own pacing. Generated text is usually smoother and more uniform than a person writing under deadline ever is.

Each page is then sent through the detector on its own, which is why the page numbers can disagree with each other and with the document score — they are separate reads, not slices of one average. Pages with almost nothing on them (a title page, a references list, a half-finished last page) are reported as unscored rather than given a number the detector can't stand behind.

WHO REACHES FOR IT

Built for people grading and editing real files

Paragraph checkers are fine for a quick gut-check. This tool is for the people who get handed finished documents and have to make a call on them:

STUDENTS AND TEACHERS

Check before you submit. Talk before you decide.

If you are a student, check your paper before your teacher does. Upload the PDF or Word file you are about to submit, see which pages read as AI, and rewrite those parts in your own words. Keep your drafts and version history: they show how the work was written, which a score cannot. No detector is 100% accurate, and writing by non-native English speakers is flagged more often (Liang et al., Stanford, 2023), so read a high score as a reason to look again, not a verdict.

If you are a teacher, use the page map to decide where to read closely, then print a one-page summary of the result to talk it through with the student. A score is a starting point for that conversation, never proof on its own; ask about drafts and sources before drawing any conclusion. Checking a whole class? The TextSight app takes up to 25 files in one batch on Pro.

READING THE RESULT

What the page scores are actually telling you

A per-page score is an estimate of how AI-like that page reads — not a confession and not proof. The most useful thing on the screen often isn't the headline number; it's the shape of the scores across the document. A draft where the writer leaned on a model for a tricky middle section will usually show a spike on those pages and lower numbers around them. A document that's uniformly high, or uniformly low, is a different story than one that swings.

Treat the result as triage. Let it tell you which pages deserve a careful read, then judge those pages yourself — checking whether the voice matches the rest of the work, whether the claims hold up, and whether the writer can talk through what they wrote. For anything with real consequences, the score should start a conversation, never end one.

HONEST LIMITS

Where it's strong, and where to be careful

No AI detector is infallible, and document-level checking has its own quirks worth knowing. Very short pages — a title page, a half-finished page, a references list — give the model little to work with, so their scores carry less weight than a dense page of prose. Heavily edited text, where someone generated a draft and then rewrote it in their own words, can read as human because, by that point, it largely is. And tables, citations and boilerplate can nudge a score in either direction without telling you much about the author.

A couple of habits keep you on the right side of all this. Don't act on a single page in isolation — read the document's pattern. Don't treat a high score as a verdict against a person, especially a non-native writer, whose plainer phrasing can look more uniform than it is. And if a result matters, pair it with the things a detector can't see: the writer's process, their drafts, and a quick conversation. Used that way, per-page scoring is a fast, honest first pass — not the last word.

GO DEEPER

How per-page detection works

Why a page-by-page map beats a single document percentage, what the scoring caps mean on each plan, and the questions worth asking any AI document detector before you trust its number — in the full AI Document Detector guide.

Read the guide →
NEXT STEP

Need a sentence-level breakdown?

Paste the text into the full AI Detector for line-by-line analysis.

AI Detector Free · no signup · 1,000 words per scan
FAQ

Document detector questions

Can I check if a PDF is AI-generated?
Yes. Drop the PDF in and you get an AI score for the whole file plus a page-by-page map, so you can see which pages carry the signal rather than just a single number for the document. Page-level scoring needs a PDF with a selectable text layer; a scanned image-only PDF has no text to read and this tool does not OCR it.
Is there a free AI detector for PDF?
This one is free to start and needs no signup — three documents a day without an account, with the first 5 pages scored individually. Those three are one allowance shared with the AI Detector and the AI Humanizer, so a document, a text check and a rewrite spend the same three. A free account reads up to 25,000 words of each document, and your first document opens in the app with every flagged sentence highlighted in its first 1,500 words.
What file types are supported?
PDF, Word (DOCX) and TXT files, up to 25 MB. Page-by-page scoring needs a PDF with a selectable text layer — DOCX and TXT have no fixed pages, so they get a document score only. Scanned image-only PDFs have no text to read and this tool doesn't OCR them.
Can I check a Word document, not just a PDF?
Yes. A Word file (.docx) is scored the same way, so you get an AI score for the whole document. What you don't get is the page-by-page map: a Word file has no fixed page boundaries the way a PDF does, so there is nothing stable to map the score onto. Export it to PDF first if you want the per-page view. Legacy .doc files are not accepted, so save as .docx.
Is a PDF AI checker the same as an AI detector?
Both names describe the same job, and the same detector runs behind both surfaces here: paste text into the AI Detector, or drop a file into this page, and it is scored by the same model. The difference is what a file adds, a score for the whole document plus a per-page map on PDFs. Pages are scored in a faster mode so a long document still returns in time, so treat a single page's number as a triage signal rather than a final verdict.
How accurate is document-level detection?
No AI detector is 100% accurate, and this one is no exception. The document score and each page score are probabilities, not proof. Human writing is sometimes flagged as AI, and writing by non-native English speakers is flagged more often (Liang et al., Stanford, 2023). Use the page map to decide which pages deserve a closer human read, and never treat a score on its own as evidence of misconduct. How we measure accuracy.
How many pages can I check for free?
Without an account you get three AI actions a day, and a document costs one of them. It is one allowance shared with the AI Detector and the AI Humanizer, so three documents, or a document and two text checks, or two rewrites and a document — any mix of three. The first 5 pages of the document are scored individually. The page map covers the first 5 pages for everyone on this page, signed in or not. Longer documents are still accepted, and the map shows where it stops. Without an account the document score itself is read from the first 1,500 words; the result says so when that happens, and a free account raises it to 25,000 words.
Is my document uploaded?
Yes — it's sent securely over HTTPS to the TextSight API and processed on our servers. The file is read in memory and not saved: we keep the scores, not the text. If you create an account from a result, the document's text is carried over to it once and deleted within the hour.
Can I check many documents at once?
On this page, one at a time. In the TextSight app, Pro and above can upload up to 25 files in one batch.
Does it work on mobile?
Yes — fully responsive.

Further reading