AI Detector – Detect AI-Generated Content with Industry-Leading Accuracy
The most trusted AI detector and AI checker on the web. Instantly scan text for ChatGPT, GPT-5.5 detector, Gemini, Claude, DeepSeek, Grok, Llama, and Mistral output. Our AI content detector gives you sentence-level highlighting, confidence scores, and detailed reports — making it the complete ChatGPT detector for academics, publishers, businesses, and creators.
AI Detector
Free AI detector for ChatGPT, Claude and AI-generated text — dual engines, multilingual support and sentence-level analysis.
Ready to Analyze
Enter your text and click Detect AI to see detailed metrics and sentence breakdown.
Detector Capabilities at a Glance
What AIDetector.cx actually provides — no inflated statistics.
Detects All Major AI Models
Our AI detector is trained on outputs from every major AI model. From GPT-5.5 detection to Claude AI detector to Gemini AI detector — all covered with model-specific fingerprinting.
Analyses perplexity and sentence-structure regularities associated with GPT-family outputs.
Detects writing patterns — burstiness, predictable transitions — common in ChatGPT-generated text.
Identifies statistical regularities present in Gemini outputs across different writing styles.
Detects vocabulary and structural patterns associated with Claude-generated writing.
Covers DeepSeek R1 and V3 outputs using shared transformer-based generation signal analysis.
Applies linguistic signal analysis to text consistent with xAI Grok generation patterns.
Supports open-weight models in the Llama family via shared generation pattern detection.
Detects statistical regularities in Mistral-generated text through entropy and phrasing analysis.
Analyses documents and emails for AI generation signals from Copilot-assisted writing.
Identifies AI-generation patterns in research summaries and AI-assisted answers.
How the AI Detector Works
Four steps from paste to verified result. The complete AI detection workflow in under 2 seconds.
Paste or Upload
Paste text directly or upload a DOCX, PDF, or TXT file. Bulk document analysis is available via the API.
Linguistic Signals Analyzed
The detection engine examines perplexity, burstiness, entropy, sentence rhythm, and other statistical patterns in the writing.
Probability Estimated
A human vs. AI probability estimate is produced for the full document and, on the full detector page, for individual sentences.
Explainable Results
Review the score alongside sentence-level colour coding and signal indicators. Two independent engine results are shown side by side.
Everything You Need from an AI Detector
Not just a score — a complete AI content detection platform with linguistic analysis, file support, and API access.
AI Probability Score
Document-level probability estimate of AI generation on a 0–100% scale.
Sentence-Level Analysis
Individual sentences are scored and colour-highlighted to show where AI signals are strongest.
Human Writing Detection
Analyses burstiness, varied sentence length, and other patterns associated with human writing.
Mixed-Content Detection
Identifies documents that appear to combine human and AI-generated sections.
File Uploads
Accepts DOCX, PDF, and TXT files. No copy-pasting required for supported formats.
Multilingual Support
Language-aware detection across 19+ languages with explicit calibration status per language.
Fast Analysis
Results are returned quickly for most document lengths. API access supports higher-volume workflows.
Signal Breakdown
Results include readability, burstiness, perplexity, and complexity indicators for further review.
Privacy-Conscious
Text is analyzed to provide the requested result and is not used to train or fine-tune detection models. Saved history can be deleted from your account.
Dual Detection Modes
Balanced and High-Sensitivity engines run independently on every analysis.
Broad Model Coverage
Analyses patterns associated with major generative models including ChatGPT, Claude, Gemini, and others.
Responsible Use Design
Results are probabilistic signals, not verdicts. Confidence levels and false-positive context are surfaced throughout.
AI Detection Benchmark 2025
Independent internal benchmarks across major AI models. Each test uses a balanced dataset of verified human-written and AI-generated samples, evaluated against our detection engine.
Varies by editing level and text length
Varies by editing level and text length
Varies by editing level and text length
Varies by editing level and text length
Varies by editing level and text length
Varies by editing level and text length
Why no accuracy percentages? Detection accuracy varies significantly by text length, writing style, language, and degree of editing. Publishing a single figure would be misleading. Results are probabilistic — they should be read as signals, not verdicts.
See the AI Detector in Action
Real detection examples. Switch between human, AI-generated, and mixed-content samples to see how our AI checker analyzes each type.
Key phrases & their AI score
Low perplexity variance, high burstiness. Varied sentence length, colloquial phrasing, and personal voice — hallmarks of genuine human writing.
Accuracy & Honest Limitations
We believe transparency builds trust. Here's exactly what our AI detection tool can and cannot do, and how to use it responsibly.
Detection Confidence
Every result includes a confidence score. High-confidence results (>90%) are highly reliable. Lower scores indicate ambiguity and should be treated as one signal, not a verdict.
False Positives
Highly technical or formal human writing (legal documents, scientific abstracts) can occasionally trigger AI signals. Always review flagged content contextually.
False Negatives
Heavily edited or "humanized" AI text may score lower on AI probability. Iterative rewriting can reduce detection signals, especially for simple prompts.
No Detector is 100% Perfect
AI detection is a probabilistic assessment, not a forensic verdict. We are transparent about this limitation. No tool — including ours — should be the sole basis for consequential decisions.
Best Practices
Combine AI detection with originality checks, style review, and direct conversation. Use our tool as an investigative aid, not a final judgment. Review sentence-level breakdown for the most reliable signal.
Responsible Use Statement
AIDetector.cx is an investigative tool, not a judicial system. Results should be interpreted by qualified humans and combined with other evidence. We oppose using AI detection scores as the sole basis for academic, legal, or employment decisions. Always extend good faith to writers.
The AI Detector for Every Professional
From academic institutions to enterprise publishers, AIDetector.cx serves every team that needs to verify content authenticity.
Students
Verify your own writing is original before submitting. Understand where AI crept into your drafts and fix it before your professor flags it.
Teachers & Professors
Screen submissions with sentence-level precision. Export reports, review highlighted passages, and make informed academic integrity decisions.
Recruiters & HR
Detect AI-written cover letters and application essays. Integrate via API into your ATS for automatic pre-screening.
Publishers & Editors
Maintain editorial standards. Screen every submitted article, guest post, and press release before it reaches your audience.
Agencies & Businesses
Quality-gate all content before publishing. Run bulk checks via API and integrate detection into your existing content workflow.
Content Creators
Prove your content is human-written to clients and platforms. Score your work before delivery and share verifiable reports.
SEO & Marketing
Google's helpful content updates reward human-first writing. Screen every page before publishing and keep your rankings safe.
The Most Accurate Free AI Detector Available
Most AI detectors give you a single number. AIDetector.cx gives you a complete picture — sentence-by-sentence analysis, model fingerprinting, linguistic metrics, and actionable confidence scores. Whether you need a quick AI text scanner or a full AI content checker workflow, we have you covered.
- Two detection modes with sentence-level analysis
- Sentence-level analysis — not just a document score
- Identifies the likely AI model (GPT-5.5, Claude, Gemini, etc.)
- File uploads: DOCX, PDF, TXT — no copy-paste required
- Full REST API for enterprise and developer integration
- Updated within days of every new major AI model release
- Submitted text is not used to train detection models
| Feature | AIDetector.cx | Others |
|---|---|---|
| AI Detection | Probability score | Varies |
| Sentence-Level Analysis | ✓ | Partial |
| Model Fingerprinting | ✓ | ✗ |
| File Upload (PDF/DOCX) | ✓ | Some |
| Multi-Language | 20+ languages | 5–10 |
| REST API | ✓ Full API | Limited |
| Humanizer Tool | ✓ | ✗ |
| Plagiarism Checker | ✓ | Separate tool |
| Free Plan | ✓ Generous | Very limited |
Complete AI Detection Guide
Everything you need to understand how AI detection works, how to use it responsibly, and how to apply it across academic, publishing, SEO, and business contexts.
After detecting AI content, consider using our AI Humanizer to rewrite flagged sections, our Plagiarism Checker to verify originality, and our API Platform to automate detection at scale.
Frequently Asked Questions
Everything you need to know about our AI detector, AI checker, and AI content detection capabilities.
Our Methodology, Standards & Commitments
We publish our detection methodology, version history, and ethical commitments openly. Transparency is core to trustworthy AI detection.
Last reviewed: June 2025 · Detection Engine v4.2
Detection Methodology
Our AI detection engine uses an ensemble approach combining perplexity scoring, burstiness analysis, token entropy measurement, and model-specific classifiers. Training data includes millions of verified human and AI-generated samples across 12 content domains.
Version History
Detection Engine v4.2 (Nov 2025) — Added GPT-5.5 classifier. v4.1 (Aug 2025) — DeepSeek R1/V3 support. v4.0 (May 2025) — Ensemble model retraining. v3.9 (Jan 2025) — Gemini 2.0 support added.
Editorial Review Process
All benchmark data and detection claims are reviewed quarterly by our research team. Accuracy figures are conservative estimates derived from internal testing; we do not report cherry-picked best-case numbers.
Security Statement
Submitted text is processed to provide the requested analysis. Signed-in history may be retained for up to 12 months and can be deleted from the dashboard. Security controls include encrypted transport and restricted database access.
Privacy Statement
We do not use submitted content to train or fine-tune our models. We do not sell user data. All processing complies with GDPR and CCPA. See our Privacy Policy for complete details.
Responsible AI Statement
AIDetector.cx is an investigative tool. We actively discourage using detection scores as the sole basis for academic, legal, or employment decisions. We publish our known limitations and false-positive rates openly.
Start Detecting AI Content Right Now
Analyze writing with sentence-level signals, confidence context, and complementary originality tools. Free to start. No credit card required.