Free AI-writing detector
Paste any text and get a stylometric human-vs-AI confidence score, with the exact signals that give AI writing away.
What it reads
The detector reads the same style markers the voice profiler does: sentence-length variance, hedging, punctuation rhythm, and the stock phrasings models fall back on. Machine-written prose tends to even out sentence length, hedge symmetrically, and reach for the same connective tissue ("moreover", "it's worth noting", "in conclusion"): habits that are measurable, not vibes.
What you get back
A human-vs-AI confidence score plus the per-signal breakdown: which specific habits in the text read as machine-written and which read as human. That breakdown is the useful part: it tells you what to change, not just whether a detector somewhere might flag you.
For the wider picture on detector reliability, we keep a sourced data page of every published accuracy figure at AI detector accuracy: every published number.
Questions
Is the AI-writing detector free?
Yes. Paste any text (an article, email, LinkedIn post) and the check runs free. Create a free account to see your result; no card is required.
How does the detector work?
It is stylometric: it reads the same style markers ScriptGrain's voice profiler measures (sentence-length variance, hedging, punctuation rhythm, and the stock phrasings language models fall back on) and returns a human-vs-AI confidence score with the exact signals that drove it.
How accurate are AI detectors?
No detector is perfect, and published accuracy figures vary widely between tools and text types. We have collected every published accuracy number, with sources and dates, at scriptgrain.com/reference/ai-detector-accuracy. Read that before treating any detector score as a verdict.
Can the detector be wrong about my writing?
Yes. Every detector produces false positives, especially on plain, well-edited prose. Treat the score as a signal, not a verdict: the per-signal breakdown shows you exactly which habits read as machine-written, which is more useful than the number itself.
Related: the free writing style analysis tool measures your own style, and a ScriptGrain voice profile measures 45 attributes and writes with them.