ParaFree’s AI detector is a free AI content detector that estimates how AI-like a text reads from four writing signals — AI phrases, sentence uniformity, vocabulary richness and structure — running entirely in your browser with no signup.
Last updated: October 29, 2026
How does the AI detector work?
It looks for patterns that are common in AI writing and gives each one a score: AI phrases (stock expressions), sentence uniformity (sentences of very similar length), vocabulary richness and structural patterns. The overall result is an estimate built from those four signals. The analysis runs in your browser, so the text is not sent to a server.
Can an AI detector prove that text was written by AI?
No — and that is true of every AI detector, not just this one. Detectors estimate from patterns; a careful human writer can score as “AI-like” and edited AI text can score as human. Treat the result as a prompt to look closer, never as evidence against someone. If a teacher has flagged your work, our guide The Truth About AI Content Detectors explains why detectors get it wrong.
When is it useful?
- Spotting the stock phrases and same-length sentences that make your own writing sound robotic.
- Seeing which parts of a draft to rewrite in your own voice.
- Getting a rough second opinion — alongside your own judgement.
How much text do I need?
At least 20 words; longer passages give a steadier estimate. Very short or very technical texts are the hardest to judge.
Why do AI detectors flag human writing?
Because the signals they measure also appear in careful human writing. Formal academic English uses stock transitions, non-native writers often keep sentences a similar length, and short texts give too little to go on. That is why a result should start a conversation, not end one.
How to check a text
- Paste the text. At least 20 words.
- Detect. Open the AI Detector tab and click the button.
- Read the signals. Look at the four signals to see what drives the estimate, and rewrite those parts if it is your own draft.
Frequently asked questions
Is the AI detector free?
Yes — free, with no signup.
Is my text sent anywhere?
No. The detector runs in your browser.
How accurate is it?
It is an estimate from writing patterns, not proof. It can be wrong in both directions, like every AI detector.
What do the four signals mean?
AI phrases (stock expressions), sentence uniformity (similar sentence lengths), vocabulary richness and structural patterns. Higher AI-likeness is shown in red, more natural in green.
What should I do if my own writing scores as AI-like?
Look at which signals are high, vary your sentence length and replace stock phrases. The natural-reading guide has tips.