Free AI Detection Checker
Paste your text below to see if AI detectors would flag it. No signup required. Instant analysis against Turnitin, GPTZero, and Originality.ai.
How AI Detection Works
AI detectors don't read your writing the way a person does. They run math on it. Two signals matter most: perplexity (how predictable the next word is) and burstiness (how much sentence structure varies throughout the text).
AI-generated text is statistically flat. Sentences cluster around the same length. Word choices are safe and predictable. The whole thing reads like it was produced at a constant temperature. Human writing? It's all over the place. Long sentence, then a fragment. Colloquialisms jammed next to formal phrasing. Tonal shifts mid-paragraph. That chaos is actually what makes it look human.
And they don't all agree with each other. Turnitin works sentence by sentence. GPTZero runs a document-wide probability model. Originality.ai stacks multiple classifiers. Same text, different scores. That's not a bug — they're measuring different slices of the same underlying signals.
What These Scores Mean
Likely Human
Good shape. Your text has natural sentence variation, diverse word choices, and enough unpredictability to look human. Most detectors would wave it through.
Mixed / Uncertain
Gray zone. Some AI-like patterns mixed with human elements. Detectors are least sure of themselves here — you might pass one and fail another. Risky to submit as-is.
Likely AI-Generated
This is going to get caught. Uniform sentences, narrow vocabulary, and telltale AI phrases throughout. Pretty much every detector would flag it.
How to Fix AI-Detected Text
Scored above 30%? You've got two paths. One costs time, the other costs money. Both work — just at very different rates:
Manual approach
- Vary your sentence lengths dramatically
- Replace AI phrases ("furthermore", "it is important to note")
- Add personal anecdotes or specific examples
- Use contractions and casual phrasing
- Break grammar rules occasionally (like real humans do)
Takes 30-60 minutes per 1,000 words. ~70% pass rate.
Anti-Turnitin (automated)
- Two-engine rewrite: LLM + statistical post-processing
- Verified against real detectors before delivery
- Matches your personal writing style
- Sentence-level heatmap shows exactly what changed
- 98% pass rate across all major detectors
Frequently Asked Questions
How accurate is this free AI detection checker?
It runs simplified heuristics — sentence uniformity, vocabulary diversity, common AI phrases — to estimate what real detectors would think. It's directional, not gospel. Turnitin uses heavier machine learning models under the hood. Think of this as a quick gut check before you submit, not a verdict.
What AI detectors does this tool simulate?
It estimates scores for the big three: Turnitin, GPTZero, and Originality.ai. Each one weighs signals a bit differently — that's why your scores won't match across all three. One might flag you at 40% while another says 65%. Normal.
Is my text stored when I use this checker?
Nope. Everything runs in your browser. Your text never leaves your device — nothing gets sent to a server. No logging, no storage, no data collection. Zero.
What makes text look AI-generated to detectors?
Statistical patterns, mostly. Uniform sentence lengths (low burstiness), predictable word choices (low perplexity), limited vocabulary, and overuse of dead giveaway phrases — 'furthermore,' 'it is important to note,' that kind of thing. Real human writing is messier. More variation, more surprises, more personality.
How can I make my AI text pass detection?
The manual route: vary your sentence lengths wildly, swap in more specific vocabulary, throw in a personal anecdote, and strip out those telltale AI phrases. That takes time and gets you maybe 70% of the way. Or use Anti-Turnitin — it rewrites AI text to clear all major detectors at a 98% rate in under 3 seconds.
Do I need to sign up to use the free checker?
No signup, no email, no account. Just paste your text and get results. Totally free.
Related Resources
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