Side by side
GPTZero vs Grammarly
A fact-based comparison built only from each tool's verified directory profile — pricing summaries, plan availability, platforms, and stated strengths and limitations. No rankings, no sponsored placement.
| Criterion | GPTZero | Grammarly |
|---|---|---|
| Category | AI Detection & Plagiarism Checking | AI Writing & Content Creation |
| In one sentence | An AI detection service that estimates whether a piece of text was written by a person, by an AI model, or by a mix of both. | A writing assistant that checks grammar, clarity, and tone as you type across websites and apps. |
| Problem it solves | Helps teachers, editors and reviewers get a signal on whether submitted writing may have been produced by AI tools such as chatbots. | Catching grammar, spelling, and clarity issues everywhere you write, not just in one editor. |
| Free plan | Yes | Yes |
| Developer API | Yes — docs | No |
| Open source | No | No |
| Platforms | Web, Chrome extension, Google Docs add-on, API | Web, Browser extension, Windows, macOS, iOS, Android |
| Pricing (summary) | Free scans are available for shorter texts, with a free account needed for longer ones; paid Professional plans (monthly or annual) and Team/Enterprise plans add premium features such as advanced scans and plagiarism checks. Student and educator pricing is mentioned. Verify current plans on GPTZero's pricing page. Checked 2026-10-13 | Free tier covers core checks; Premium adds advanced suggestions. Verify current plans on Grammarly's site. Checked 2026-10-05 |
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How to choose
Both profiles link to the vendors' official pricing — plan details change often, so verify there before buying. Pick based on the criterion rows above that matter to your workflow, not on rankings: we don't rank tools, because the right choice depends on your needs.