AI Detector

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naturally for Grammarly AI Detector.

Grammarly, the widely used writing assistant, has added an AI-detection feature that estimates how much of a document may have been generated by AI. Here's how that scoring actually works, what its false-positive record looks like, and the honest version of what a humanizer can and can't do about it.

How Grammarly AI Detector works

Grammarly's AI detector estimates the share of a document that appears to have been produced by a large language model such as ChatGPT, Claude, or Gemini, reporting a percentage rather than a hard yes-or-no. Like other detectors it reads statistical regularity — how predictable the word choices are and how evenly the sentences are paced. Text that is consistently predictable and uniform reads as machine-written, while human writing tends to be more varied.

False positives

Grammarly's estimate is probabilistic, not proof, and AI detectors broadly misfire on real human writing. False positives cluster on formulaic, simple, or non-native and ESL English, whose low perplexity and steady cadence resemble AI output. A high AI percentage is a signal, not a verdict — treat any single score that way.

Where we stand We measure every rewrite against Sapling's AI detector and show you the score, so you can see how natural the output reads. We do not claim to pass Grammarly's AI detector or any specific detector — their models change frequently and no humanizer, including ours, can guarantee passage at every moment. Anyone selling "100% undetectable guaranteed" is making a promise the technology can't keep. What Humanizer does is rewrite the rhythm, word choice, and structure that detectors key on, and let you match your own voice.

What a rewrite actually looks like

Here's the same paragraph before and after Humanizer — the structure, rhythm, and word choice change, not just a few swapped synonyms. The percentage is Sapling's AI-likelihood estimate, shown on every rewrite. It's a signal, not a guarantee against Grammarly AI Detector.

Before/after on a sample paragraph. Scores are Sapling estimates and will vary by text — Humanizer never promises a clean pass on any detector.
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FAQ

Grammarly AI Detector questions, answered.

Yes, Grammarly added an AI-detection feature that estimates how much of a document may have been AI-generated. It reports a percentage rather than proof, so its result is a signal rather than a verdict.