Analysis
Do AI Detectors Actually Work?
AI detectors have had a rough press. There have been high-profile cases of students falsely accused based on detector scores, non-native English speakers flagged for writing in a "too formal" style, and tools confidently declaring that passages from the King James Bible were AI-generated.
So should you trust them? The honest answer is: it depends entirely on what you're using them for.
What AI detectors are actually measuring
Most AI detectors — including this one — don't work by recognising specific AI outputs. They work by measuring statistical patterns that correlate with machine-generated text:
- Sentence length variance (AI tends toward uniformity)
- Vocabulary distribution (AI overuses certain words)
- Transition phrase frequency (AI loves "furthermore" and "moreover")
- Perplexity — how predictable the text is, word by word
- Burstiness — how much the writing rhythm varies
The problem is that these patterns also appear in well-edited human writing, highly formal writing, and writing by non-native speakers who've been taught to write in an academic register. A detector measuring "too formal" will flag all of these.
Where they work well
AI detectors are most reliable when dealing with raw, unedited AI output — text pasted directly from ChatGPT or similar without any human editing. In these cases, the patterns are strong and consistent, and a good detector will score it 80%+ with accuracy.
They're also useful as a self-check tool — if you've used AI to help draft something and want to know how robotic it still sounds before sending it, a detector score gives you a useful starting point for editing.
Where they fail
Detectors struggle with:
- Lightly edited AI text — even a few passes of human editing drops scores significantly
- Formal academic writing — it genuinely shares patterns with AI output
- Short texts — under 150 words there's not enough signal to score reliably
- Non-native English writers — formal second-language writing patterns overlap with AI patterns
How to use them responsibly
For teachers and educators
A high detector score should prompt a conversation, not an automatic penalty. Use it as one data point alongside your knowledge of the student's prior work, the submission timeline, and a direct discussion.
For writers checking their own work
Very useful. You know whether you used AI or not — the score tells you how robotic it still sounds and the flagged passages show you exactly what to edit.
For making hiring or academic decisions
Not reliable enough on its own. A detector score is not evidence. Don't use it as the sole basis for any consequential decision.
The bottom line
AI detectors are useful tools with real limitations. They work best as a first-pass filter or a self-editing aid. They shouldn't be treated as authoritative proof of anything. Used with that understanding, they're genuinely helpful — used without it, they can cause real harm.
Try our free detector — built to show you exactly which passages triggered the score, not just a number.
Check your text free →