Check your paper's AI percentage and plagiarism before you submit
PaperCheck scores your research paper, thesis or project report sentence by sentence, shows exactly which lines read as AI-written, and finds copied text from the papers you cite. Free for 5,000 words.
Check your paper freeYour paper is deleted as soon as the check finishes.
How it works
1. Upload
Word (.docx), PDF, or paste text. Up to 30,000 words per check.
2. Check
AI-text detection on every sentence with its surrounding context, plus a plagiarism check against arXiv papers.
3. Fix
See the flagged sentences, then fix them yourself or hand them to your own AI assistant with a ready-made prompt.
What your report looks like
Chapter 5 explains the implementation, training procedure, baselines and evaluation protocol. The model was trained for 40 epochs on the full dataset, with the learning rate halved after epoch 25. Chapter 6 reports and discusses the results, including significance tests and ablations.
Illustrative example. Highlighted sentences are the ones to rewrite first.
AI checker and plagiarism checker in one
AI percentage, sentence by sentence
Two open AI-text detectors score each sentence in context. You get the share of words flagged, the same measure Turnitin's AI report uses, and an estimate of the Turnitin AI score.
Plagiarism against real papers
Your text is compared with the full text of the papers you cite on arXiv, and with related arXiv papers found from your key terms. Copied phrases are shown with their source.
Built for academic writing
Only prose is checked, from the abstract to the references. Tables, captions, equations and the reference list are left out, as in Turnitin.
Free limits
| How you use it | Free words |
|---|---|
| On this website, after signing in with Google | 5,000 words |
| From your own AI assistant (ChatGPT, Claude, Gemini, Cursor) | 20,000 words |
Use PaperCheck from ChatGPT, Claude or Gemini
Add PaperCheck to your AI assistant as a connector (MCP) with one link. Then just say "check my paper": your assistant runs the AI and plagiarism checks, sees exactly which sentences are flagged, rewrites only those, and checks again.
Connector link: https://paper-check.me/mcp. Get your personal key on the check page.
Frequently asked questions
Is PaperCheck the same as Turnitin?
No. PaperCheck is an independent tool and is not affiliated with Turnitin. It estimates the AI percentage with open AI-text detectors, scored sentence by sentence the way Turnitin reports the share of flagged words. Use it as a pre-submission check, not a guarantee.
How is the AI percentage calculated?
The prose from the abstract to the references is split into sentences. Each sentence is scored with the two sentences before and after it. A sentence counts as flagged when the detector's score is above 50%, and the AI percentage is the share of words in flagged sentences.
What does the plagiarism check compare against?
The full text of the papers you cite that are on arXiv, plus related arXiv papers found by searching with your key terms. It reports copied phrases of eight or more words with their source. It does not search the whole web.
Is my paper stored or used for training?
No. Your paper is deleted as soon as the check finishes and is never used to train anything. Only the scores and flagged snippets are kept for your report.
How do I lower my AI percentage?
Rewrite the highlighted sentences: vary sentence length, use the specific details of your own work instead of general phrases, and cut stock words such as "furthermore", "crucial" or "leverage". Keep every number, citation and technical term unchanged.