Short answer: Does Turnitin flag Grammarly? Mostly no for grammar fixes, likely yes for rewrites. Turnitin says its detector is "not tuned to target Grammarly-generated spelling, grammar, and punctuation modifications" (Turnitin FAQ). Text from Grammarly's generative features is a different story.
Does Turnitin flag Grammarly grammar fixes?
Turnitin does not flag Grammarly grammar fixes in most cases, and it tested this on human-written documents with 0 AI text in them. Its FAQ says changes made by Grammarly and other grammar checkers were mostly "not flagged as AI-written by our detector". Spelling, punctuation and small grammar fixes leave your sentences yours.
The key word is "most". Turnitin does not say never, and its own AI Writing Report guide says the model "may not always be accurate". So accept grammar fixes one at a time rather than all at once, and keep your own phrasing where it already works.
When does Turnitin flag Grammarly text?
Turnitin will likely flag Grammarly text when 1 of Grammarly's generative features wrote it, not you. The FAQ names draft generation, paraphrasing and summarising, then says: "Content produced using these features will likely be flagged as AI-generated by our detector."
Turnitin goes further on paraphrasing. If Grammarly's paraphrasing tool is used to modify AI-generated text, Turnitin says it "will likely be flagged as AI-generated by our detector". Our guide to humanizers versus paraphrasers explains why reworded AI text still scores high.
Which features make Turnitin flag Grammarly text?
Turnitin does not flag Grammarly suggestions of every kind. The line sits between 2 kinds of help: fixes and rewrites. Turnitin's FAQ treats spelling, grammar and punctuation fixes as low risk. It treats draft generation, paraphrasing and summarising as likely flags. Use that split to decide which suggestions to accept on a graded essay.
| Grammarly use | Turnitin's view |
|---|---|
| Spelling and punctuation fixes | Mostly not flagged |
| Small grammar corrections | Mostly not flagged |
| Paraphrasing or rewriting sentences | Likely flagged |
| Generating a draft or summary | Likely flagged |
Check your course rules too. Some courses allow proofreading tools and ban generative rewriting, and that policy matters more than any detector score.
How often does Turnitin flag Grammarly edits on your own essay?
Turnitin usually does not flag spelling fixes on work you wrote yourself, but light editing can push your writing towards the predictable phrasing detectors look for, and no detector is perfect. A Springer study tested 14 detectors and found none above 80% accuracy.
Turnitin also needs at least 300 words of prose to score a file, and it shows an asterisk instead of a number for scores under 20%. If you see *%, the score is too low to report. Our AI detector comparison explains how Turnitin scores differ from other detectors. For hands-on editing, see our writing with AI guide.
How can Grammarly Authorship help if Turnitin flags your essay?
Grammarly Authorship records how you wrote a document, which a detector cannot do from the final file alone. Grammarly's page says "AI detectors only guess from the final draft" (Grammarly). It works in 3 places: Microsoft Word, Google Docs and Canvas submissions.
Turn it on before you start. Grammarly's support page says Authorship "only tracks writing from the moment you turn it on" (Grammarly Support). Turnitin itself says its AI score "should not be used as the sole basis for adverse actions against a student", so process evidence carries real weight.
FAQ
Does Turnitin flag Grammarly spelling and grammar fixes?
Mostly no. Turnitin's FAQ says its detector is not tuned to target Grammarly spelling, grammar and punctuation changes, and in its tests most were not flagged.
Does Turnitin flag Grammarly paraphrasing?
Likely yes. Turnitin says text from Grammarly's generative features, including paraphrasing and draft generation, will likely be flagged as AI-generated.
Does Turnitin flag Grammarly if I use it on every essay?
Usually not for spelling and grammar fixes. Check your course policy first, and avoid rewrite and paraphrase features on graded work.
What should I do if Turnitin flags my Grammarly-edited essay?
Share your drafts and version history, or a Grammarly Authorship report if you turned it on. Turnitin says its score should not be the sole basis for action against a student.
Does Turnitin flag Grammarly on short assignments?
It cannot score them at all. Turnitin needs at least 300 words of prose before it gives an AI score.
