AI detector

Check AI writing signals sentence by sentence.

Penlify shows an overall AI probability and highlights the sentences worth reviewing. A free account lets you try the detector; the score is a signal, not proof of who wrote the text.

Try the AI detector Analyze clarity without signup
Sentence-level review Clear probability labels No authorship guarantees

What the Penlify AI detector shows

A useful review separates the overall pattern from the exact sentences that may need attention.

Overall AI probability

Use the document score to understand the broad pattern. Do not treat a percentage as a verdict about authorship or misconduct.

Sentence-level signals

Find the sections with repetitive structure, unusually uniform phrasing, or other patterns the model associates with generated writing.

A focused editing path

Review highlighted sentences for clarity, specificity, evidence, and voice instead of rewriting an entire document blindly.

How to use an AI detector responsibly

Start with the context. A polished research abstract, a formulaic business email, and a short student paragraph can all look statistically predictable for different reasons. Paste the complete passage when possible, because a single sentence rarely provides enough evidence for a meaningful classification.

  1. Run the complete draft and record the overall score.
  2. Review sentence-level results instead of reacting only to the headline number.
  3. Check highlighted sentences for vague claims, repeated transitions, uniform sentence length, and missing personal or domain-specific detail.
  4. Edit for accuracy and reader value, then run the detector again only as a comparison.

What an AI detector cannot prove

No detector can reliably establish who wrote a passage from the text alone. Human writing can trigger false positives, especially when it is formal, concise, translated, heavily edited, or written by someone using a predictable structure. AI-assisted writing can also receive a low score. Treat results as probabilistic evidence that supports review—not as a disciplinary decision.

If your goal is clearer writing rather than AI classification, use the free writing analyzer. It runs in your browser and checks readability, rhythm, filler phrases, and possible passive constructions without uploading your text.

AI detector questions

Is the Penlify AI detector free?
Penlify includes AI detection on its free account plan. An account is required because detection uses Penlify's server-side analysis. The separate clarity analyzer works without an account.
Can an AI detector be wrong?
Yes. False positives and false negatives are possible. Scores should be reviewed alongside drafts, sources, revision history, and the writer's explanation.
Does a high AI score prove cheating?
No. A detector score does not prove authorship or intent. Penlify is designed as a writing-review tool, not as a standalone basis for accusations or penalties.
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