What is an AI Detector?
An AI Detector is a tool that analyzes text for statistical patterns associated with AI language models — primarily perplexity (how predictable each word is) and burstiness (how much sentence rhythm varies). It then returns a probability score for how likely the text is to be AI-generated.
It's free to use and commonly applied to writing produced by models like ChatGPT, Gemini, and Claude. Teachers, editors, hiring managers, and writers use it as a second signal before making an editorial or academic integrity decision — not as a final verdict.
It's worth knowing that AI detectors can produce false positives, flagging genuine human writing as machine-generated, which is exactly why the score should inform a decision rather than make it. If you're trying to make AI-assisted writing read more naturally, pair this with our AI Humanizer.
How Does an AI Detector Work?
AI detectors don't actually "know" whether a machine wrote something. They make a statistical guess based on two measurable signals in the text: perplexity and burstiness. Perplexity measures how predictable each word is to a reference language model, since models like ChatGPT and Gemini are trained to pick the most statistically likely next word, which produces smooth but predictable text. Burstiness measures how much sentence length and rhythm vary across a passage; human writing naturally mixes short, punchy sentences with long, winding ones, while unedited AI output tends to keep a steadier, more uniform pace.
This tool analyzes both signals together, rather than relying on either one alone, since detectors that lean on a single metric produce far more false positives and false negatives. The tool returns a probability score, not a verdict, because that's simply all any AI detector can realistically offer. No detector can see how a piece of text was actually written; it can only compare statistical patterns against what it has learned to associate with machine-generated language.
Why Accuracy Drops on Short Passages
Accuracy matters most for short passages. Detection confidence drops sharply on text under roughly 200 words, and heavily edited AI text can score as human even when a machine wrote the first draft. Understanding what the score actually measures, rather than treating it as a lie detector, is the difference between using this tool responsibly and misusing it to make an accusation you can't actually support.
What Detectors Can and Can't Confirm
No AI detector, including this one, can prove authorship. It can only flag statistical patterns that correlate with machine-generated text. For situations where you want a second opinion on the writing itself, our Grammar Checker and AI Paraphraser can help clarify the language without changing the underlying meaning.
Why Use an AI Detector?
For anyone reviewing submitted writing, a percentage score alone is rarely enough to act on. An AI detector is most useful when it adds an objective signal alongside the human judgment you're already applying.
- ✅ Get a Second Signal — Add objective data points to a suspicion before raising it with someone
- ✅ Check Your Own Writing — See if your natural style reads as unusually uniform or predictable
- ✅ Editorial Screening — Flag submissions that may need a closer human read before publishing
- ✅ Understand the Score — See a breakdown, not just a single number, so you can judge context
- 🚀 Ready in Seconds — Paste your text and get a full analysis with nothing to install
Features & Capabilities
- Dual-Signal Analysis — Combines perplexity and burstiness instead of relying on one metric alone
- Sentence-Level Breakdown — Highlights which specific passages scored highest for AI likelihood
- Multi-Model Coverage — Checks patterns associated with ChatGPT, Gemini, and Claude output
- Instant Results — Full analysis completes in seconds after you paste your text
- Nothing to Install — Runs entirely in your browser, no account or download needed
Who Uses an AI Detector?
- Educators — Screen submissions for further review, alongside a direct conversation with the student
- Editors & Publishers — Add a data point when evaluating freelance or user-submitted content
- Hiring Managers — Get a second signal on written work samples during a hiring process
- Writers — Check whether their own drafts read as unusually flat or uniform
- Content Teams — Spot-check large volumes of submitted copy before publishing
Key Benefits of an AI Detector
- 🚀 Informed Decisions — Base editorial or academic conversations on data, not just a hunch
- 🔍 Transparent Scoring — See what actually drives the result instead of a black-box number
- ⏱️ Fast Screening — Check large volumes of text quickly before a deeper manual review
- 🌐 Always Available — Works from any browser, any device, any time
- 🆓 Free to Use — No subscription needed for standard detection
Best Practices for Using an AI Detector
- Never Treat a Score as Proof — False positives happen, especially on short or formal text
- Check Text Length First — Accuracy drops significantly on passages under 200 words
- Talk to the Person — A direct conversation reveals more than a percentage ever will
- Consider Writing Style — Some human writers naturally produce low-burstiness, formal prose
- Combine With Other Evidence — Use detection results alongside process, drafts, and context
- Offer a Follow-Up Path — If the flagged text needs humanizing, point toward our AI Humanizer as one tool among several