Grammarly AI Detector Review 2025: Can It Really Catch AI-Generated Text?

You’re tweaking an essay or post, running it through Grammarly’s AI detector to prove it’s yours, when—wham!—it says it’s AI-written, even though you poured your heart into it. Total bummer, right? I’ve been there, stressing over false flags and questioning these tools. Want to know how Grammarly’s AI detector ticks, if it’s legit, and how to skip those pesky errors? This guide’s got you. We’ll unpack Grammarly’s features, weigh its ups and downs, and check out Toolsmart’s Undetectable AI Rewriter—

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my fave for keeping text real and detector-proof.

Part 1: Grammarly AI Detector Overview

Grammarly’s AI detector tries to catch machine-made text by looking at tone, sentence flow, and word patterns. It’s baked into their Premium plan, meant to help students, writers, and pros make sure their work doesn’t get pegged as AI stuff like ChatGPT’s. I ran it on some of my own writing and AI text, and honestly, it’s hit or miss.

Features:

• Detects AI content using pattern analysis (e.g., syntax, predictability).

• Integrated with Grammarly Premium’s grammar, tone, and plagiarism tools.

• Works in the Grammarly Editor, web apps, and plugins (e.g., Google Docs, Word).

• Provides a percentage score for AI likelihood.

Pros:

• Seamlessly built into Grammarly’s platform, so no extra tools needed.

• Easy to use with a familiar interface.

• Combines AI detection with grammar and plagiarism checks.

Cons:

• Not transparent about how it calculates AI scores, leaving you guessing.

• Struggles with long documents or hybrid (human + AI-edited) content.

• High false positives—sometimes flags human writing as AI, which stressed me out. 

Grammarly’s detector is handy for quick checks, but those false positives are a real pain, especially for students or pros worried about being flagged unfairly. It caught basic ChatGPT text but tripped up on my rephrased drafts, which was annoying.

Part 2: How to Use Grammarly AI Detector

Using Grammarly’s AI detector is pretty straightforward, but you’ll need a Premium account to access it. I ran a blog post through it to see how it works, and here’s the breakdown.

Steps:

Step 1: Fire up Grammarly’s Editor on the web or desktop, or use its plugin in Google Docs or Word.

Step 2: Pop in your text or upload it (free version caps at 1200 words, Premium handles more).

Step 3: Hit the “Plagiarism and AI Text Check” button down in the bottom-right corner.

Step 4: Check out the AI score (like “50% AI-generated”) and any highlighted bits.

If your text is super long, break it into smaller chunks—Grammarly can choke on big files. Got a false positive? Try tweaking a few sentences to shift the score. I had to mess with a paragraph twice to drop a 35% AI flag on my own stuff. Keep your original draft handy in case you need to prove it’s yours.

The process is simple, but the lack of detail on why text is flagged as AI frustrated me. I got a 58% AI score on a story I wrote years ago, which made no sense. It’s useful but not reliable enough to trust blindly, especially for academic or professional work.

Part 3: A Smarter Solution—Toolsmart AI Undetectable Rewriter

1. Toolsmart Undetectable Rewriter Overview

Toolsmart’s Undetectable AI Rewriter is a free, web-based tool that rewrites and humanizes text to make it sound natural and dodge AI detectors like Grammarly’s. It’s perfect for refining AI-generated content or ensuring your writing passes as human. I used it to tweak a ChatGPT draft, and it made it read like I wrote it myself.

Features:

• Rewrites text to sound human and bypass AI detection.

• Fast, ad-free, and no login required.

• Works on any device (phone, tablet, desktop).

• Supports multiple tones (formal, casual, professional).

Pros:

• Completely free with no word limits.

• Clean, intuitive interface—no pop-ups or distractions.

• Preserves meaning while making text natural.

• Reduces AI detection flags significantly.

Cons:

• No batch processing for multiple texts.

• Limited to web, no dedicated app.

Toolsmart’s rewriter is a lifesaver. I ran a 300-word AI draft through it, and it came out so natural that Grammarly’s detector gave it a 0% AI score. It’s my top pick for avoiding false positives without losing the text’s vibe.

2. Comparison Table: Toolsmart AI Undetectable Rewriter vs. Grammarly AI Detector

Comparison Notes: Grammarly’s detector is great for catching obvious AI text but often misflags human writing, especially if it’s polished or rephrased. Toolsmart, on the other hand, rewrites text to sound natural, slashing the chances of being flagged. It’s faster, free, and doesn’t need a login, unlike Grammarly’s Premium-heavy approach. I found Toolsmart’s output passed most detectors, including Originality.ai, with flying colors.

3. How to Use Toolsmart AI Rewriter

Toolsmart’s Undetectable AI Rewriter is dead easy to use, and I tested it with a ChatGPT-generated post to see how it holds up.

Steps:

Step 1: Head over to Toolsmart.ai and click on “Undetectable AI Rewriter.”

Step 2: Drop your text—whether it’s AI-made or your own—into the input box.

Step 3: Pick a tone, like casual or formal, then hit “Rewrite.”

Step 4: Grab the rewritten text by copying it or saving it as a file.

Tips: Run the new text through an AI detector like Quillbot’s to make sure it reads human—I did, and it got a 0% AI score. Hang onto your original text for comparison. It works like a charm in Safari on iPhone or Chrome on Android.

Toolsmart’s rewriter is a breeze. It turned a robotic ChatGPT draft into something that sounded like me in seconds. No ads, no login—just results. It’s perfect for dodging Grammarly’s overzealous flags.

FAQs

Q1: Can Grammarly’s AI detector catch all types of AI writing?

Nope. It’s decent with basic ChatGPT output but struggles with rephrased or hybrid content, often flagging human writing as AI.

Q2: Will Toolsmart’s Undetectable AI Rewriter guarantee 100% undetectability?

No tool’s perfect, but Toolsmart greatly lowers detection chances, making text sound human. I tested it, and it passed most detectors with ease.

Q3: Is Grammarly’s AI detector reliable for academic use?

It’s evolving but too prone to false positives for serious academic work. Double-check manually or use Toolsmart to rewrite for safety.

Q4: Is Toolsmart’s Undetectable AI Rewriter really free?

Yup, totally free—no login, no limits, no catch. I used it for multiple drafts without a hitch.

Q5: Can Toolsmart’s rewriter handle long documents?

It works best for shorter texts (under 1000 words). For longer pieces, break them into chunks to avoid slowdowns—I did this with a 1500-word report.

Q6: How does Toolsmart compare to other AI humanizers?

Toolsmart’s faster and free compared to paid options like Undetectable AI, and its human-like output beats Grammarly’s inconsistent detection.