The short answer
Using Grammarly to fix spelling, grammar and punctuation in your own writing is generally not treated as AI writing, and Turnitin says those changes were not flagged in most of its tests. Using Grammarly’s generative AI features to draft, rewrite, paraphrase or summarize text is different: that is AI-generated content, Turnitin says it will likely be flagged, and many course policies treat it like any other AI tool. Whatever you use, your course policy decides what is allowed.
Two kinds of AI in Grammarly
Grammarly answers this question directly in a support article on how it uses AI and whether it triggers AI detectors. It describes two different things:
- Foundational AI. Since 2009, Grammarly has used machine learning, natural language processing and input from linguists to make suggestions for spelling, grammar, clarity, conciseness and tone. Grammarly says this “does not change the substance of the writing”, and that it cannot be turned off separately from the product, because it is what the suggestions are.
- Generative AI. In 2023 Grammarly added optional features that “produce new content based on their inputs or prompts”. Grammarly says these are not turned on by default, are used on demand, and “can generate content and meaningfully change writing”.
So the honest answer to “is Grammarly AI?” is yes, but that is not the question a teacher or a detector is asking. The question is whether the words, ideas or structure came from you or from a model. Correcting a comma does not change that. Asking a tool to write a paragraph does.
Which features are which
Grammarly’s guide to generative AI assistance says its on-demand generative features help you “compose, rewrite, ideate, and reply”. You reach them by selecting text and clicking a pencil or lightbulb icon or a sidebar, by prompting AI Chat, or through Superhuman Go, an AI assistant that can answer questions, brainstorm, draft content and polish text. Older articles call these features GrammarlyGO.
| What you do in Grammarly | Which kind it is, per Grammarly | How a course is likely to see it |
|---|---|---|
| Accept spelling, grammar and punctuation fixes | Foundational AI suggestions | Usually allowed, like a spell checker |
| Accept word choice or clarity suggestions on a sentence | Traditional, non-generative features (Grammarly’s Authorship article calls them this) | Usually allowed; check the policy if it limits editing tools |
| Ask it to rewrite a paragraph, change its tone or length | Generative AI (paragraph-level rewrites) | Often treated as AI use; may need permission and disclosure |
| Ask it to draft, outline, summarize or brainstorm | Generative AI (AI Chat, Superhuman Go, compose) | AI-generated content; follow the policy on AI tools |
The last column is our reading of how policies commonly work, not a rule. Your instructor’s policy is the only one that counts.
Turning generative AI off
If you want to stay clearly on the correction side, Grammarly says any user can turn off generative AI in the Feature customization tab of their account settings. In the desktop apps it is under Settings, Customization, Generative AI, and in the browser extension it is in the dropdown menu, according to Grammarly’s help page. On Grammarly for Education and business accounts, admins decide whether members can use generative AI at all; Grammarly’s admin guide lists the AI assistant, strategic suggestions and paragraph-level rewrites as the switches. If your school provides Grammarly and the features are missing, that may be why.
Can Turnitin detect Grammarly?
Turnitin answers this in its AI writing detection FAQ, under the question “If students use Grammarly for grammar checks, does Turnitin detect it and flag it as AI?”. Its answer has two halves:
- Grammar checks: generally not flagged. Turnitin says its detector “is not tuned to target Grammarly-generated spelling, grammar, and punctuation modifications”, and that in tests on human-written documents, changes made by Grammarly (free and premium) and other grammar-checking tools were, in most cases, not flagged as AI.
- Generative features: likely flagged. Turnitin says this excludes content made with Grammarly’s generative AI features, “including draft generation, paraphrasing, summarizing, and other features”, and that content produced with them “will likely be flagged as AI-generated”.
Note the words “in most cases”. Turnitin does not promise that corrected text is never flagged, and no detector can. Turnitin also says its score should not be the sole basis for action, and that students cannot see the AI report themselves. Our guide on whether Turnitin detects AI covers how that report works, and AI detector false positives explains why human writing is sometimes flagged.
Grammarly’s position on detectors is similar. Its support article says AI detectors can help assess whether text appears AI-generated, but that “none today can reliably and conclusively determine whether AI was used”, and that a result should be one data point, not the only evidence.
The gray areas
Most problems come from the middle of the table, not the ends.
- Accepting every rewrite. Taking sentence-level suggestions one by one, while reading them, keeps the writing yours. Selecting a whole paragraph and asking for a rewrite hands the wording to a model, and Turnitin lists paraphrasing among the generative features that will likely be flagged.
- “I only used it to make it sound better.” If the ideas are yours but the sentences came from a generative feature, many policies still count that as AI assistance that needs to be disclosed.
- Summarizing sources. Using a generative feature to summarize a reading you then quote from produces AI text, and also risks misrepresenting the source.
A worked example
A student writes a 1,200-word essay in Google Docs, accepts Grammarly’s comma and spelling fixes, and takes a few word choice suggestions. That is correction, and by Turnitin’s account unlikely to be flagged. A second student writes the same essay, then selects the introduction and conclusion and asks Grammarly to rewrite them to sound more academic. Those two paragraphs are now generative AI output. If the course bans AI writing tools, that is the part that breaks the rule, whether or not a detector notices. If the course allows it with disclosure, a one-line note saying which paragraphs were rewritten with Grammarly’s generative AI resolves it.
What your course policy means
Policies on AI vary a lot between institutions, and even between courses at the same school. Before you rely on any Grammarly feature for graded work, look for three things:
- Whether the policy names Grammarly or “AI writing assistants”. Some allow grammar checkers explicitly and ban generative tools. Some ban all AI tools, which can be read to include Grammarly’s generative features.
- Whether disclosure is required. If AI use is allowed with a statement, say which tool, which features and for what. If you need to cite it, our guide to citing AI tools shows the formats.
- Who to ask. If the wording does not settle it, ask your instructor in writing before you submit. A short email asking “is Grammarly’s rewrite feature allowed for this assignment?” protects you far better than a guess.
For the broader question of when AI help becomes misconduct, see is using AI plagiarism?
Protecting yourself
The best defence against a wrong accusation is evidence of how you wrote the work. Three practical habits:
- Keep version history. Write in Google Docs or Word with version history on, and do not paste in a finished essay from somewhere else. A history that shows the text growing over several sessions is strong evidence.
- Consider Grammarly Authorship. According to Grammarly’s Authorship help article, when you turn it on in Google Docs (through the browser extension) or Microsoft Word (through the desktop app), it records the source of text as you write: typed, pasted from a website, pasted from an unknown source, AI-generated, or typed and then changed with its AI rephrasing. It also labels text edited with non-generative features such as grammar corrections. Grammarly’s Authorship page says it does not track without your consent, that you decide when to share the report, and that it can replay the writing process. It is opt-in, and it only covers documents where you turned it on.
- Disclose what you used. If you used generative features and your course allows it, say so in the way the course asks. If you only used corrections, it does no harm to mention that too.
If you want to see how a detector reads your draft, the Plagiarism Checker Plus AI detector gives a sentence-level view. It is free without an account up to 1,000 words, a free account includes 3,000 words a month, the text needs at least 50 words, and it is never used to train AI models. It is a separate tool, so it cannot tell you what Turnitin will show. Use it to find passages worth rereading, not to tune a score. If you have already been flagged, follow how to prove you didn’t use AI.