Quillbot Review (2026): Can Turnitin Detect It? Accuracy & Humanizer Test

In the academic world of 2026, Quillbot has become the most controversial tool in a student's arsenal. Unlike ChatGPT, which generates new ideas from scratch, Quillbot is designed to take existing text and rewrite it. For years, this was the "secret weapon" to bypass plagiarism checkers and improve flow.

But with the rise of advanced AI detection systems like Turnitin, Copyleaks, and ZeroGPT, the game has changed. Students and professionals alike are frantically searching: "Can professors detect Quillbot?", "Is the AI detector accurate?", and "Does the Humanizer actually work?"

This deep-dive review answers those questions with 2026 data, testing Quillbot against the toughest detectors on the market and analyzing whether the Premium subscription is truly worth the cost.

What is Quillbot used for?

Quillbot is primarily an advanced Paraphrasing Tool powered by Natural Language Processing (NLP). It restructures sentences, swaps synonyms, and improves fluency without altering the original meaning. While it started as a simple thesaurus-swapper, it has evolved into a comprehensive writing suite.

• The "Humanizer" Effect: Students often paste robotic, AI-generated text from ChatGPT into Quillbot to make it sound more natural and less repetitive.
• Fluency Mode: This mode is a lifesaver for ESL students, fixing awkward grammar and sentence structure to ensure the text reads like a native speaker wrote it.
• Academic Mode: Transforms casual or conversational language into formal, research-paper-ready prose, perfect for thesis work.
• Freeze Words: A critical feature that lets you lock specific terms (like "mitochondria," "World War II," or specific proper nouns) so the AI doesn't change them during the rewrite process.

The Big Question: Can Turnitin Detect Quillbot?

This is the #1 query we see. The answer is nuanced and critical for anyone in academia.

Quillbot vs. ZeroGPT vs. Copyleaks

We tested Quillbot's "Humanizer" capability against leading detectors to see if it could bypass them:

Detector	Detection Rate (Standard Mode)	Detection Rate (Creative Mode)
ZeroGPT	High (Flagged as AI)	Medium (Mixed results)
Copyleaks	Very High (Flagged)	High (Flagged)
Turnitin	High	Low (If manually edited)

Is Quillbot's Own AI Detector Accurate?

Quillbot offers its own free AI detector tool. Is it reliable compared to the industry giants?

Verdict: It is decent but lenient.
In our tests, Quillbot's detector often marks text as "Human" that ZeroGPT marks as "AI." It tends to err on the side of caution to avoid false positives. It serves as a good "first line of defense" for self-checking, but you should not rely on it exclusively if your university uses Turnitin, as Turnitin is much more aggressive.

Quillbot Premium: Is it Worth It?

Many users ask "Is Quillbot Premium worth it?". Here is the breakdown of why you might upgrade:

• Unlimited Words: The Free plan caps you at 125 words per paraphrase. Premium is unlimited. If you are rewriting a 10-page thesis or a long blog post, Premium is mandatory to avoid copying and pasting dozens of times.
• Compare Modes: Premium lets you see outputs from "Formal," "Simple," "Creative," and "Shorten" modes side-by-side. This allows you to pick the best sentence structure for your specific context.
• Plagiarism Checker: Premium includes 20 pages/month of plagiarism scanning. While valuable, heavy users writing multiple papers might still need a dedicated tool like Scribbr or Grammarly Premium which offers more volume.
• Faster Processing: Premium servers process text almost instantly, whereas the free version can lag during peak hours.

Is Quillbot Safe & Legit?

Yes. Quillbot is a legitimate SaaS company owned by Learneo (the same company that owns Course Hero). It is safe to use and does not steal your essays to sell to other students, a common myth. However, "Safe" does not mean "Undetectable." Use it as a writing aid to improve your own thoughts, not a cheating tool to generate work you didn't do.

Frequently Asked Questions

1. How to uninstall Quillbot from Mac?

Quillbot often installs as a Word Add-in or a Chrome Extension, which can be confusing to remove.
For Word: Open Word > Insert > My Add-ins > Right-click Quillbot > Remove.
For Chrome: Right-click the Quillbot icon in your toolbar > Remove from Chrome.

2. Can I use Quillbot for University?

Check your syllabus carefully. Most universities allow spell checkers and grammar aids like Grammarly and Quillbot but ban "Generative AI" like ChatGPT. Using Quillbot to polish your own words is usually acceptable. Using it to spin a Wikipedia article or an AI-generated essay is considered plagiarism.

3. How to cancel Quillbot Premium?

To stop billing, go to Account Details > Your Plan > Cancel Subscription. Note: You must cancel before the renewal date to avoid being charged. They generally do not offer refunds for "forgotten" subscriptions once the charge has gone through.

4. Why does Quillbot say everything is AI?

If you paste highly formal, rigid academic text into an AI detector, it often flags as AI even if a human wrote it. This happens because formal writing lacks "burstiness" (variation in sentence length and structure). This is a common "False Positive" issue with all detectors, not just Quillbot's.