AI Checker for PDF: free online tool
AI Checker for PDF scores every sentence of a PDF for how likely it is to be AI-generated and paints the result straight onto your document, so you can see at a glance which passages read as machine-written.
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How to use AI Checker for PDF
- Open AI Checker for PDF and choose your PDF.
- Run the check in your browser or in Advanced AI mode.
- Download the highlighted PDF with the report page.
What you can do
- Sentence-level highlights inside the original PDF
- Per-page AI scores and a summary report page
- Batch mode checks many PDFs at once
Two ways to run AI Checker for PDF
In your browser
Stylometric checks plus a small neural classifier on your device. Unlimited.
Advanced AI
Adds transformer detectors on our private GPU server and fuses their sentence scores.
Privacy and where your file is processed
In browser mode the PDF never leaves your device. Advanced AI mode: needs a free account, runs on our own private GPU server (not a cloud AI provider), is never used for training or shared with third parties, and the upload and result are deleted automatically after processing.
Free usage limits
Free to use. In your browser: no account, no file-size limit and no usage limit. Advanced AI mode (our private GPU server): free account with 150 credits a month (1 credit per page for OCR and PDF to Word), files up to 50 MB and 100 pages. There is no paid tier.
Frequently asked questions
Does it work on scanned PDFs?
It needs selectable text. Run OCR PDF first, then check the searchable result.
How reliable is it?
No AI detector is perfect. Treat the highlights as a guide for review, never as proof.
Which AI models can it detect?
It looks for writing patterns common to ChatGPT, Claude, Gemini and similar chatbots, and for machine-translated text. It does not identify which model wrote a sentence.
Can teachers check student essays with it?
Yes, it is useful to see which passages deserve a closer look. Because false positives happen, especially with formal or non-native writing, talk to the student before drawing conclusions.
Which languages does it support?
It works best on English and Turkish text. Other languages get a score, but with lower confidence.
Can I check many PDFs at once?
Yes. Batch Processing has an "AI check & highlight" operation that checks every PDF and returns the highlighted files in one ZIP.