Plagiarism Checker for PDF — Read Locally, Check in Real Time

Drop a PDF, we extract its text on your device with pdf.js, then run the same honest real-time check against OpenAlex, Crossref and Wikipedia. The file is never uploaded.

Quick answer: Check a PDF for plagiarism free: the PDF is read locally in your browser (pdf.js), its text is extracted and checked in real time against OpenAlex, Crossref and Wikipedia.

🌐 General-web mode — add your own free Google key (optional)

The default check runs against open scholarly + Wikipedia sources. To also scan the general web, create a free Google Programmable Search key (100 queries/day free) and paste it below. The key is stored only in your browser (localStorage) and is sent only to Google's official endpoint.

How to use

Choose or drop your PDF (text-based, not a scan).
The text is extracted locally — you can review and edit it.
Press Check and inspect every match's live source link.

About this tool

Students are usually handed their brief in PDF form and asked to hand one back — so this checker speaks PDF. The file is opened with pdf.js entirely on your device: the text layer is extracted, and only short search queries from that text go out to the named open sources. Image-only scans have no text layer, and we detect and tell you that honestly instead of returning a fake 0%.

FAQ

Is my PDF uploaded to a server?

No. pdf.js opens and reads the file inside your browser; only short search queries derived from the extracted text are sent to the source APIs.

It says 'no text layer' — why?

Your PDF is a scan (images of pages). Text extraction needs a digital text layer. Run an OCR tool first, then paste the text into the main checker.

Which sources are checked?

The same honest set as the main tool: OpenAlex, Crossref and Wikipedia in real time, plus optional general-web mode with your own free Google key.

How large a PDF can I check?

The engine checks the 12 longest key sentences per run — enough to profile a typical essay or report chapter. Very large theses: check chapter by chapter.

Is it free?

Completely — no signup, no watermark, no per-day cap imposed by us (source APIs may apply their own fair-use limits).

Does it work on iPhone/Android?

Yes — file picking and checking work in modern mobile browsers.

Rate this tool

Your rating stays in this browser (local storage) — nothing is sent to any server.

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📑

The complete plagiarism checker pdf guide

Prefer the long version — a worked example, the mistakes people actually make, and answers to real questions? The blog guide Plagiarism Checker Pdf — Complete Guide, Mistakes & FAQ covers all of it step by step.

Browse the collection: PDF Tools — All 37 Free Online Tools

Plagiarism Checker for PDF — Read Locally, Check in Real Time

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About this tool

FAQ

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