| Quick Answer: QuillBot is more accurate than ZeroGPT in AI detection. Independent tests such as Scribbr and IntoTeMinds also suggest that the accuracy of QuillBot is much higher than ZeroGPT. The false-positive rate of ZeroGPT is also higher, and the overall accuracy in high-stakes conditions is not reliable for ZeroGPT. However, many question Quillbot’s accuracy because its frequent reviewer, Scribbr, is a sister company. |
ZeroGPT Vs. QuillBot: How Are These Two Tools Different?
ZeroGPT and Quillbot are both free AI detectors.
However, both differ in the limits and the level of accuracy.
| Feature | ZeroGPT | Quillbot |
| Cost | Free, unlimited use | Free to 1,200 words per checkPremium $8.33/month billed annually. |
| Scribbr 12-tool test | 64% accuracy, 1 false positive | 78% accuracy, 0 false positives. |
| IntoTheMinds average | 68% (last place) | 91.25% (first place). |
| Typical false positive reports | 14.6% to 33% | Low in most tests. |
| Known weakness | Formal and academic prose | Missed Claude samples in one test. |
How ZeroGPT And Quillbot Work Differently?
ZeroGPT and Quillbot are very different as AI detectors.
ZeroGPT functions as a standalone tool for free AI detection.
On the other hand, Quillbot is a complete writing suite performing the following functions.
- Paraphrasing
- Summarizing
- Grammar Checking
- AI-Detector
- AI-Humanizer
Here, also make a note that, as they share the same parent company, Learneo, Scribbr, and Quillbot run on the AI detection engine of Quillbot.
Partially, that is why questions are often raised regarding the accuracy of the Quillbot detection rate.
Why Is Ownership Important To Assess The Accuracy Of Quillbot Objectively?
In April 2026, Scribber conducted a test of the best AI tools.
In this test, Quillbot is rated as the second-best AI detector, and ZeroGPT gets the 7th position.
The same test says that Quillbot has an accuracy rate of 78%, and the AI detection accuracy rate of ZeroGPT is 64%.
Now, anyone referring to this review report would find Quillbot way more trustworthy.
Very few people know that Scribbr and Quillbot come from the same parent company.
However, to bolster the claim of Quillbot as a more powerful AI detection tool, I also checked the IntotheMinds assessment.
Quillbot scored the highest in it with an accuracy of 91.25%.
Having said that, Quillbot showed some limitations in detecting texts written by ChatGPT 5.
So, instead of relying blindly on Quillbot for AI detection, you must know how you can ethically use AI for studying.
Also, for academic papers and research, add a proper AI use disclosure statement along with your submissions.
ZeroGPT Vs. QuillBot: A Detailed Analysis Of The Accuracy Rate
As a writer, I cannot trust ZeroGPT alone for AI detection.
I have to run it through Copyleaks or another trusted AI detection tool.
The independent assessments only establish that.
ZeroGPT
ZeroGPT promises an accuracy rate of 98% in AI detection.
However, most independent results depict a different story for the accuracy of ZeroGPT.
According to a benchmark 160-text test in 2026, ZeroGPT has shown an accuracy rate of 73.8%.
Furthermore, for human-written text, the false-positive rate of AI detection is 20.5%.
Again, in a different analysis of 37,874 essays, ZeroGPT recorded a false-positive rate of 26.4%.
Moreover, based on the in-house AI detection test of essaywritingguides, we found a high false-positive rate of around 31%.
In addition, the IntotheMinds assessment has placed it in the last position with an accuracy rate of 68%.
Quillbot
As I have mentioned, IntotheMinds has placed Quillbot as the best AI detector in its test.
However, despite an accuracy rate of 91.25%, it is not the best tool for the detection of ChatGPT 5.
QuillBot is not the only tool with limitations in detecting ChatGPT 5.
Even Turnitin is inconsistent in detecting ChatGPT 5 texts.
Again, I checked a few pieces written by Claude in the free tool of QuillBot, and it could not detect them.
It agrees with the Pangram test, in which Scribbr’s free tier detected none of the three Claude samples.
A Third Test
StoryChief ran one AI-assisted article through several detectors.
Against an original estimate of 74.36% AI, QuillBot returned 63% and ZeroGPT only 19.36%.
So, ZeroGPT undercalled the AI content.
What These Numbers Finally Say About The Accuracy Of These Two Tools?
We know that AI detectors work on perplexity and burstiness factors.
So, the scores or results they show are probability and not real scores.
Also, the accuracy of an AI detection tool depends on two factors simultaneously.
The first one is how the tool is flagging AI-written or machine-written texts.
Also, is it detecting human-written texts as AI-written?
This is a common problem I face with ZeroGPT.
Also, in my experience, I have found ZeroGPT to err in both ways.
Moreover, check the same article at a difference of a few hours and the detection result will change.
The problem of false positives is even higher in academic or business writing, as those write-ups mostly have a formulaic structure.
Thus, they are more refined or formulaic, impacting the perplexity and burstiness scores.
ZeroGPT Vs. QuillBot: Features And Workflow
As I have mentioned, QuillBot works as a full-fledged writing suite.
On the other hand, ZeroGPT is a standalone tool for AI detection.
QuillBot
In QuillBot, I have to paste text or upload a file to get the AI percentage score.
There is a free tier, and a premium tier of QuillBot costs $8.33 per month on annual billing.
However, a subscription of Quillbot is beneficial considering it also has grammar and paraphrasing tools.
Having said that, in ethical practices, you must use the paraphrasing tool only for understanding a concept or ideation.
If you use the detection tool for AI detection and use the paraphraser to bypass AI, it does not make any sense.
ZeroGPT
ZeroGPT is popular among writers for a quick check because it is free and offers a quick report.
Also, it supports different languages and offers a label like “Your Text is Human written.”
Still, its accuracy is always in question.
Honestly, I only use it when I just need to add a screenshot of the AI detection score as a formality, and I have written it entirely on my own.
Practical Limits Of ZeroGPT Vs. Quillbot
Like most AI detectors, ZeroGPT and Quillbot both work on probabilities, and both tools show three limitations.
Length
When you paste shorter or brief text into these tools, the result is highly impacted.
Also, ZeroGPT can only detect up to 15,000 characters in the free tier.
Edited And Paraphrased Text
ZeroGPT and Quillbot can both detect AI even if you lightly edit or tweak AI-written texts.
However, if you do deep editing, the detector tools will fail to detect the machine-written text.
So, reliability is a concern if you ask, “Can AI detectors detect paraphrasing or not?”
For me, it is an even a bigger concern when using Quillbot as it has a paraphraser and a detector both.
Fairness
A study by Liang et al. found a 61.3% average false positive rate on TOEFL essays across seven detectors for non-native English writers.
This happens because the perplexity level is lower and the choice of vocabulary is more generic in non-native English writers or students.
It is not a healthy practice when vocabulary beats accuracy.
Why Human Writing Gets Flagged By These Detectors?
Human writing often gets flagged by these AI detectors for the following reasons.
- Clean Grammar
- Uniformity in Sentence Length and Structure or Lack of Burstiness
- Predictable Choice of Words
- Lack of a Personal Voice.
Moreover, there are higher false positives in academic and business writing because those are stoic or formulaic in nature.
What To Do If A Detector Flags Your Writing
- Keep dated drafts and version history, which show how your work developed.
- Run the text through a second detector and compare which passages each tool questions.
- Be ready to explain your process, sources, and choices in a conversation.
- Disclose permitted AI help under your course policy.
ZeroGpt Vs. QuillBot: The Key Takeaways
- QuillBot generally outscores ZeroGPT in independent tests, but some tests come from related companies.
- ZeroGPT’s false positive rate is the main concern, especially for formal writing.
- Neither tool is suitable as sole evidence of AI use.
ZeroGPT vs. QuillBot: Which Tool Should You Choose?
This answer depends on who you are and why you are using the AI detector.
ZeroGPT is an ideal choice for easy and free access and a quick personal check.
However, its lower accuracy rate and high false positives stop it from being a solo AI detector.
On the other hand, QuillBot has fewer reported false alarms.
So, start there and use ZeroGPT only as a second opinion.
However, if you are using an AI detector for academic or research-related write-ups, neither of these tools will be enough.
In such cases, you must use something more reliable, like Turnitin.
Also, irrespective of the tool you use, you must keep your drafts ready and have a strong and ethical defense to prove that you have not used AI for writing.
