The rise of automated writing tools has never been faster, and one question keeps coming up: how can we distinguish text produced by artificial intelligence from that written by a real person? With the democratization of ChatGPT, Claude, and Gemini, the detection of AI-generated content is becoming a strategic need, whether in education, publishing, journalism, or even corporate communications.

However, the issue is far from simple. AI detectors are not infallible; some produce false positives, while others struggle to recognize hybrid texts (partially edited by humans). Thus, choosing the right tool is not just a matter of raw efficiency, but also of the ability to interpret results with nuance and adapt to specific use cases. We conducted tests on 100 texts, half of which were written by humans, to evaluate the accuracy and reliability of the main AI detectors. By comparing their strengths, limitations, and preferred use cases, here are the results we obtained.

Comparative Table of AI Detectors

GPTZero

GPTZero has made a mark by quickly becoming a reference in the academic world. Its accuracy rate is high, with the ability to correctly identify human texts while minimizing false positives. In our tests, it achieved a 96% detection rate and a 0% false positive rate, a rare score in this sector. It is very well-calibrated for English but has also shown its effectiveness for Spanish and French.

The tool is not limited to binary detection. It provides pedagogical feedback on the reasons for its analysis, making it useful for teachers who want to explain to students why a text is suspected of being AI-generated. The transparency of the process enhances its credibility.

GPTZero integrates additional features like writing replay and source verification, offering a more complete view of the student’s or writer’s work. In a professional context, this level of granularity helps protect an organization’s reputation by avoiding the publication of poorly controlled artificial content.

GPTZero offers 10,000 credits for free each month, usable for basic analyses and with a limitation on text size. Ideal for testing the detector’s effectiveness or for periodic use. Beyond that, and for more advanced insights, a monthly or annual subscription is required.

WAIZZ AI Detector

WAIZZ AI Detector is a free tool designed for academic and professional use to identify AI-generated text. Its interface allows users to paste text or upload documents for analysis, highlighting passages potentially written by AI and assigning a humanity score to assess the authenticity of the text.

In tests conducted on 100 texts, it detected 96% of AI-generated content and generated a false positive (2%). It should be noted that these errors of judgment occurred only in very short texts. The tool has shown consistent performance in English, French, Spanish, and German.

WAIZZ offers suggestions for optimizing text to improve readability, but these features and the analysis of texts longer than 1,200 words require to register on the web application.

Winston AI

Winston AI positions itself as a solid alternative thanks to its line-by-line analysis. Unlike other tools that only provide an overall score, Winston offers a detailed view with a “confidence level” for each suspicious passage.

Test results show that Winston has an excellent balance – with a 92% detection rate and a 10% false positive rate, making it one of the most reliable tools for detecting AI content. It is therefore a relevant option for publishers and journalists who need to quickly verify the authenticity of articles or opinion pieces.

Its interface remains accessible, with clear reports and possible integration into editorial workflows. The fact that the tool can handle large volumes of text without loss of performance makes it attractive for teams producing content on a large scale.

Copyleaks AI Detector

Copyleaks is known for its versatility. It detects AI content in 30+ languages, which places it among the few truly multilingual detectors. Moreover, it explains why a text was deemed suspicious, a feature that many competing tools do not offer.

In terms of performance, Copyleaks detected 100% of AI texts in our tests but also generated a false positive rate of 25%. It is therefore a very strict tool, which may be suitable in contexts where an excess of caution is preferred over an omission. The free version is limited in the number of queries but does not seem to be reduced in its accuracy; notably, it allows for the analysis of texts up to 2000 words. The free version is limited to 10 analyses per day.

Another advantage, but this time in the paid version, is that Copyleaks combines AI detection and plagiarism checking. For publishers and schools, this means a one-stop-shop for controlling both the originality and the human nature of the content.

QuillBot AI Detector

QuillBot is already well-known as a paraphrasing tool, and its AI detector complements its ecosystem. The advantage is being able to analyze both generated texts and those that have been modified via reformulation tools, at least for English texts. The tool is slightly less precise when it comes to analyzing texts in other languages.

Our tests show mixed results with a detection rate of 78%, which can be considered inconsistent, but 0% false positives. It tends to miss some AI texts and to over-interpret certain human passages.

Despite these limitations, QuillBot has the advantage of being completely free, with no usage restrictions. It is an acceptable solution for users already familiar with its ecosystem, but it does not stand as a benchmark in pure detection.

Scribbr AI Detector

Scribbr is a free solution that has gained visibility through a simple and accessible approach. It provides paragraph-by-paragraph detection, allowing for a detailed analysis without the need for overly technical reports.

In terms of accuracy, Scribbr achieves the exact same score as QuillBot: 78% detection and 0% false positives. This leads us to believe that QuillBot and Scribbr use the exact same algorithm (and the same interface, for that matter). Therefore, Scribbr is not the most reliable either, but it has the advantage of being fast and requiring no registration. For occasional or academic use, it is a practical choice.

Scribbr also has the benefit of supporting multiple languages, which broadens its use. Its positioning is therefore to offer a free and intuitive solution, even if it means sacrificing some accuracy.

Sapling

Sapling differentiates itself by offering a complete suite that includes AI detection, plagiarism control, and fact-checking. Its focus is clearly on web publishers and content agencies looking to publish reliable and original articles.

However, test results show limitations with a false positive rate of 34%, especially on academic texts. On the other hand, its ability to identify AI texts is considered excellent as it reaches 100%. Thus, it stands out as a powerful tool for controlling the overall quality of content but can be too strict in certain situations.

In terms of interface, Sapling offers a clear and collaborative dashboard, which facilitates its adoption by writing teams. It is a tool designed for sustained professional use, with the logic of a complete platform.

Originality AI

Originality created a huge buzz upon its release, helped by many influencers and YouTubers paid handsomely to speak highly of it. In reality, Originality is certainly not the ultimate AI detector that some describe. Its very good detection score (100% according to our tests) comes at the cost of an extremely high false positive rate (38%). This flaw is explained by the rigidity of its latest model, which visibly struggles to recognize a genuinely human text when the writing style is formal or academic.

The same goes for multilingual detection, which proved to be imprecise and did not convince us. While we can commend the relevance of its plagiarism verification tools and fact-checker for verifying the truthfulness of information, in pure detection and for academic work, it is certainly not a reliable solution.

ZeroGPT

ZeroGPT has managed to gain popularity, largely by riding on the confusion with the much more reliable GPTZero. However, its DeepAnalyse technology proves to be disappointing and unreliable. Our tests are conclusive: with a detection rate of just 64% and 32% false positives, it is wrong far too often.

Its supposed multilingual analysis lacks coherence to the point of seeming random, and worse, the tool is disconcertingly easy to fool. Simply changing a few words is enough to reverse its verdict, turning an AI text into a human one.

Ultimately, its free nature does not compensate for its lack of reliability. ZeroGPT is a tool that generates more doubts than certainties and should not be used for a serious evaluation.

Undetectable AI

Undetectable AI has a feature that sets it apart, as it not only detects a text but also offers to transform it to make it “undetectable,” effectively acting as an AI content humanizer.

While its detection performance on artificial texts is excellent at 98%, this effectiveness is nullified by a very high false positive rate of 62%, making it absolutely unreliable for evaluating a human text.

This is why this tool is controversial, as it reflects a trend where users are looking less to identify than to bypass detectors. Its use must therefore be considered with caution, particularly in contexts where content integrity is a priority.

Final Verdict

It goes without saying that not all AI text detectors are created equal. WAIZZ AI Detector, GPTZero (not to be confused with ZeroGPT), and Winston AI stand out for their accuracy and reliability, even when faced with texts produced by the latest generation of language models. These tools are perfectly integrable into a verification routine within academic and professional environments. Not to mention that WAIZZ is entirely free, while GPTZero offers a limited but still very competitive free plan.

Winston AI and Copyleaks can also be very well used to meet heavy editorial needs, although Copyleaks should be handled with awareness of its somewhat high false positive rate. For their part, Quillbot and Scribbr, which share the same algorithm, are better advised as a second layer of verification rather than as a primary tool.

Conversely, it is better to avoid certain tools for a serious analysis. Solutions like Sapling are far too strict, with an excessive number of false positives. As for ZeroGPT and Undetectable AI, their lack of reliability and their business models raise serious questions about their integrity, disqualifying them for rigorous use. The essential thing is to maintain human vigilance, as no solution is yet infallible.

Choosing an AI detector is not just about comparing scores. It is about aligning the tool with its objective, whether that is to preserve academic integrity, secure sensitive communications, or simply check a text quickly. The key is to maintain human vigilance, as no solution is completely infallible.

Our Testing Methodology

To ensure the reliability of this comparison, we adopted a rigorous methodology. Our evaluation is based on the analysis of a corpus of 100 varied texts, including 50 texts written by humans (excerpts from academic articles, blogs, and professional content) and 50 texts generated by different LLM models (including ChatGPT, GPT-5, GPT-4o, Claude 4 Sonnet, and Gemini 2.5 Pro). Text lengths varied between 100 and 800 words to reflect diverse use cases. To reflect international usage, the majority of these texts were in English, but a significant portion was tested in French, Spanish, and German to evaluate multilingual performance.

Each text was individually submitted to all the listed detectors. The “detection rate” corresponds to the percentage of AI texts correctly identified, while the “false positive rate” represents the percentage of human texts incorrectly flagged as being generated by an AI. This approach allowed us to measure not only the effectiveness of each tool but also its reliability and its tendency to make errors.

Important: We would like to clarify that no compensation was received from the companies whose tools are mentioned in this article. This comparison was conducted with complete independence and contains no affiliate links. Our sole objective is to provide a factual and objective analysis to help our readers choose the tool best suited to their needs, preserving the integrity and impartiality of our editorial approach.