What Is GPTZero Online?
GPTZero Online is a free browser-based AI detection tool that shows how content detectors would score your writing before you submit it. Paste any text and get an instant AI probability score with sentence-level highlighting — no account needed.
Key Features
- Free AI Detection — No payment required for basic checks
- Instant Results — AI probability score in seconds
- Sentence-Level Highlighting — See exactly which sentences trigger flags
- No Signup — Paste and check immediately
- Multi-Detector Insights — Understand how GPTZero, Turnitin, Originality.ai would score your text
Who Is It For?
Students — Check essays before Turnitin flags them. Even human-written papers get false positives when writing is too polished.
Content Writers — Verify that AI-assisted drafts read as human before publishing. Avoid client complaints or SEO penalties.
Professionals — Review cover letters and reports before sending to employers who run AI checks.
How It Works
- Paste your text into the detector
- Review your AI probability score and flagged sentences
- Revise or submit with confidence
The engine evaluates perplexity (word unpredictability) and burstiness (sentence variation) — metrics where human writing differs from AI output.
AI Detector Comparison
We tested 6 major detectors on 20 samples. No single tool scored above 85% accuracy. GPTZero caught 9/10 AI texts but flagged 2 human samples. Turnitin had zero false positives but missed 3 AI texts. Light editing reduced detection by 20-30% across all tools.
Get Started
Visit gptzero.online — paste your text, see your score in seconds, submit with confidence.
