AI Detector · 14 tools
Best AI Detector Tools (2026)
Compare AI detectors for text and content, including accuracy, free scans, plagiarism checks, and API access.
All AI Detector tools
Undetectable AI is a free AI content detector and text humanizer. Paste text to instantly check whether it was generated by ChatGPT, Gemini, Claude, Llama, or other models, with results from multiple AI checkers.
This free Turnitin AI Detector preview analyzes pasted text to highlight AI-generated passages. Unlimited words with no signup required for quick checks.
MyDetector is a free AI content detector and humanizer. It identifies text generated by ChatGPT, Claude, Gemini, and other AI writers and offers a companion humanizer to rewrite detected content.
AI Detector is a free AI content detection tool with no word limits. It identifies AI-generated text from ChatGPT, GPT-5.4, Claude, Gemini, and other models with 99.1% accuracy, offering sentence-by-sentence analysis.
Sightengine is an image and video moderation API. Detect nudity, violence, weapons, drugs, text overlays, AI-generated content, and more with simple REST endpoints trusted at scale.
What is an AI detector?
An AI detector estimates whether text — and sometimes images — was generated by AI rather than a human. It analyzes patterns like word predictability and phrasing and returns a probability score. Detectors are used to screen essays, articles, and submissions, though none is perfectly accurate.
Core features to look for
- AI-vs-human probability score for text
- Sentence-level highlighting of flagged passages
- Support for common models (GPT, Claude, Gemini)
- Bulk or document upload checks
- Plagiarism checks in some tools
- Free tier and API access
Who uses AI detectors, and how
Check text for AI
Teachers, editors, and hiring teams screen essays, articles, and submissions.
Image & content detection
Some tools flag AI-generated images or mixed human-AI content.
Free scans
Compare free detectors by word limits, accuracy claims, and daily quota.
API & bulk
Integrate detection into an LMS, CMS, or moderation pipeline.
How does an AI detector work?
AI detectors run classifier models trained on human and AI text. They measure signals like how predictable each word is (perplexity) and how uniform the phrasing is (burstiness), then output a probability. Because AI writing keeps improving, scores are estimates, not proof.