AI Content Detector: Deep Text Analysis to Find AI-Written Sections
Know exactly which sentences in your paper were written by AI. Our detector colour-codes every sentence and assigns it a score from 25 (human) to 75 (AI-generated) · Results in 15 minutes · from $0.29/page.
How the AI Content Detector Analyses Your Text
Rather than returning a single percentage, the detector applies deep text analysis to break down your document sentence by sentence and shows you where AI content is concentrated.
Upload Your File
Send your document as .docx, .pdf, .txt, .odt or .rtf. Up to 50 MB, up to 999 pages. No account required.
Perplexity & Burstiness Analysis
The engine measures perplexity (how predictable each word choice is) and burstiness (how varied sentence lengths are). AI text scores low on both — humans are naturally more unpredictable.
Colour-Coded PDF Report
Your report highlights AI-flagged sentences in red and human-written sentences in green, each with a numeric score. You can see the problem at a glance and revise accordingly.
What AI Models Are Detected?
The AI content detector covers all major language models used to generate academic text.
ChatGPT & GPT-4
OpenAI models are responsible for the majority of AI-generated academic content. GPT-3.5 and GPT-4 both produce text with characteristic patterns the detector identifies reliably.
Claude (Anthropic)
Claude is known for producing especially polished, academic-sounding prose, making it a common choice for essay assistance. The detector identifies Claude output at the sentence level.
Gemini (Google)
Google Gemini is increasingly popular for research tasks. The detector covers Gemini Pro and Gemini Ultra text with the same sentence-by-sentence precision.
Llama & Mistral
Open-source models power many third-party writing assistants. Llama 2, Llama 3 and Mistral are all covered, even when accessed through unofficial tools.
Mixed & Edited Content
Papers where some sections are AI-generated and others are human-written are particularly well served by sentence-level detection — each section is evaluated independently.
New Models Continuously Added
As new AI systems emerge, the detection model is updated to recognise their output. Your scan always uses the latest version of the detector.
What the Score 25–75 Means for Your Content
The score scale avoids the false precision of a percentage. Instead, each sentence is placed on a spectrum with 25 anchoring natural human writing and 75 marking text that carries strong AI-generation signals.
This approach reflects reality: most flagged academic papers do not contain 100% AI content. They contain a mixture — an AI-drafted introduction, a human-written methods section, an AI-generated conclusion. Sentence-level scoring makes this mixture visible.
- Score around 25: Characteristic human voice and rhythm
- Score 40–55: Ambiguous — possibly AI-assisted or formal writing
- Score around 75: Strong AI-generation indicators
- Report available as colour-coded PDF
Simple, Transparent Pricing
No subscription. Pay per page. Minimum order $0.90.
Plagiarism Scan
Check against 70+ billion sources
- 70+ billion sources
- Results in 15 minutes
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Combo: Plagiarism + AI
Complete academic integrity check
- Full plagiarism check
- Sentence-level AI detection
- Colour-coded PDF report
- Best value per page
AI Scan
AI content detection only
- Sentence-by-sentence scores
- All major LLMs covered
- Results in 15 minutes
- Email delivery
Questions About the AI Content Detector
An AI content detector analyses the statistical properties of text. AI-generated content tends to have low perplexity (predictable word choices) and low burstiness (uniform sentence length variation). Our tool measures these signals at the sentence level and assigns a score from 25 (human) to 75 (AI-generated).
A single document-level score is misleading — most academic papers contain a mix of human and AI-written passages. Sentence-by-sentence analysis lets you see exactly which paragraphs or sections are flagged, so you can address specific passages rather than guessing where the problem lies.
The detector flags text generated by any major language model including ChatGPT, GPT-4, Claude, Gemini, Llama and Mistral. It also catches AI-written content that has been lightly edited, though heavily rewritten text may score lower.
Yes. While the tool is optimised for academic writing, it works equally well for blog articles, marketing copy, reports and other professional documents. Upload any text-based file in .docx, .pdf or .txt format.
A plagiarism checker compares your text against existing sources and flags verbatim or near-verbatim matches. An AI content detector analyses the intrinsic statistical properties of the text itself — it does not need a matching source to flag AI-generated content. The Combo plan runs both checks simultaneously.
See Exactly Which Sentences Are AI-Written
Upload your paper and get a sentence-by-sentence AI content report delivered to your inbox in 15 minutes.
Use code plagiarism-scan10 for 10% off.