Why is Grammarly saying my writing is AI?

Why Grammarly Might Flag Your Writing as AI-Generated

It’s a growing concern: you’re writing an original essay, email, or report—entirely in your own words—and Grammarly suddenly flags it as “AI-generated.” Confusing, right? The truth is, Grammarly isn’t accusing you of copying from ChatGPT. Instead, it’s recognizing patterns shaped by its own tools.

Grammarly uses generative AI under the hood to power features like “Rephrase,” “Rewrite,” and “Use our best version.” These tools are designed to refine your writing, making it clearer and more polished. But here’s the catch: when you rely on them, the output often carries the stylistic fingerprints of AI—consistent tone, predictable phrasing, and high fluency. That’s exactly what AI detectors are trained to spot.

So if you’ve used Grammarly’s suggestions heavily, especially the more aggressive rewrites, it’s not surprising that another AI detector might label your text as machine-generated. Your ideas may be 100% human, but the language has been smoothed over by algorithms designed to optimize clarity and correctness—ironically, making it too clean to seem natural.

This doesn’t mean you should stop using Grammarly. It’s still one of the best tools for catching grammar slips and improving readability. But it’s worth remembering: the more you lean on AI-powered rewrites, the more your writing starts to sound like AI—even if you came up with the core message yourself.

The solution? Use Grammarly as a guide, not a ghostwriter. Keep your unique voice, quirks and all. Edit selectively. And when authenticity matters—like in personal statements or creative work—trust your instincts over the “best version” button. After all, real writing isn’t about perfection. It’s about being heard.