Grammarly's AI detection, explained

Updated June 10, 2026

Grammarly sits inside the writing process itself — which makes its move into AI detection and authorship tracking different in kind from paste-in checkers. Here's what it sees, who sees it, and how to keep your text reading like you.

Detection plus authorship

Grammarly offers two relevant things: a conventional AI detector (paste text, get a likely-AI percentage) and Authorship, which records how a document came together as you write — typed by hand, pasted from elsewhere, or generated by AI. Authorship is aimed squarely at the academic false-accusation problem: it lets a student prove their process, not just assert it.

That cuts both ways. Provenance tracking helps honest writers — and it makes "I pasted it from my notes" a checkable claim.

What its detector measures

The paste-in detector reads the same statistical fingerprint as everyone else: predictable word sequences and uniform sentence construction. Grammarly is unusually frank that detectors are fallible and shouldn't be sole evidence — a stance worth citing if you're ever falsely flagged.

Living with an editor that watches

  • If you used AI assistance where it's allowed, humanize the draft in Humanize Studio so the final text carries your rhythm — facts stay verbatim.
  • Verify with the built-in detector before submission or send.
  • Where Authorship-style provenance is in play, transparency beats masking: keep drafts, cite AI help if your context requires disclosure.
  • Use our false-positive guide if you're accused over work you actually wrote.

Our position

Humanize Studio is built for the same world Grammarly's Authorship anticipates: one where verification beats assertion. Humanize your text, see a real score, never have the text stored on our servers — and where disclosure rules exist, follow them. No tool changes what your institution or employer permits.

Frequently asked questions

Does Grammarly detect AI writing?

Yes — it has a free AI detector, and its Authorship feature tracks how documents were composed (typed, pasted, AI-generated) for users who enable it.

Can Grammarly tell my professor I used AI?

Grammarly doesn't report you; Authorship produces a record the document owner can choose to share. Institutional Grammarly deployments may have their own policies — worth checking what your school has enabled.

Is Grammarly's detector accurate?

Comparable to other mainstream detectors, and Grammarly itself emphasizes detectors should not be sole evidence of misconduct. Cross-check anything important.

Humanize it — then verify it

Paste your text, get a rewrite that reads like a person wrote it, and check the AI-probability score yourself before anyone else does. 3-day free trial.