AI Content Detector
Paste any text and get a statistical likelihood score for whether it was written by AI. Analyzes sentence uniformity, AI vocabulary, transition word density, and more.
Signal Breakdown
Low variance in sentence length suggests AI (AI writes more uniformly).
Words and phrases statistically overrepresented in AI-generated text.
Heavy use of formal connectives like "furthermore" and "moreover".
Avg words per sentence. AI tends toward longer, complete sentences.
Detected AI Terms
About This Free Online AI Content Detector
Our free AI content detector analyzes text for the statistical patterns that distinguish AI-generated writing from human text. It examines four signals: sentence uniformity (AI produces more consistent sentence lengths than humans), AI vocabulary (words and phrases disproportionately common in AI outputs, like "delve", "tapestry", "transformative", and "it's worth noting"), formal transition word density (AI overuses connectives like "furthermore" and "moreover"), and average sentence length (AI tends toward longer, complete sentences). Each signal scores from 0 to 100 and the tool combines them into an overall likelihood score with a verdict of "Likely AI-written", "Uncertain", or "Likely Human-written". No API call is made — all analysis runs locally in your browser. Results are heuristic estimates and should not be used as definitive proof.
Features of Our AI Content Detector
- Overall AI likelihood score (0–100) with a plain-English verdict
- Four signal breakdown: sentence uniformity, AI vocabulary, formal transitions, sentence length
- Lists detected AI vocabulary terms with occurrence counts
- Debounce-triggered analysis — updates as you type
- Requires 50+ words for a reliable result
- 100% private — no text is uploaded, no API is called
How to Use the AI Content Detector
Using this tool is simple and requires no signup or registration. Follow these steps:
- Paste the text you want to check into the input box (minimum 50 words).
- The detector analyzes the text automatically and shows an overall likelihood score.
- Review the four signal bars to see which patterns contributed to the score.
- Check the "Detected AI Terms" list to see which specific words or phrases were flagged.
Frequently Asked Questions About AI Content Detector
How accurate is this detector?
It uses statistical heuristics rather than a trained ML model, so it is not 100% accurate. It works well as a quick first-pass check, especially for generic or template-heavy AI outputs. Highly polished or edited AI text may score low; unusual human writing styles may score high. Do not use it as definitive proof either way.
What does the Sentence Uniformity signal measure?
AI models tend to generate sentences of similar length — the coefficient of variation (stdev ÷ mean) across sentence lengths is low. Human writers naturally vary sentence length more, resulting in a higher coefficient of variation. Low uniformity → high AI score.
Which words count as "AI vocabulary"?
A curated list of words and phrases statistically overrepresented in AI-generated text: single words like "delve", "tapestry", "transformative", "seamlessly", and "nuanced", plus multi-word phrases like "in today's digital landscape", "it's worth noting", and "comprehensive overview".
Why does it need at least 50 words?
Statistical signals like sentence-length variance and vocabulary density are not reliable on very short texts. With fewer than 50 words, a single unusual sentence can wildly skew the burstiness score, making the result meaningless.
Is my text sent to a server?
No. All analysis runs locally in your browser using JavaScript. Your text is never uploaded, logged, or stored.
Is this tool free to use?
Yes, completely free with no signup, no limits, and no usage tracking.
Why Choose Text Toolbox?
Text Toolbox provides free, private, and instant online text tools. Unlike other text utility websites that require signup accounts or send your data to servers, all our tools process your text entirely in your browser. This means your content never leaves your device — we cannot see it, store it, or share it. Our tools are fast, lightweight, and work on any device with a modern web browser.