“A tool that can identify text written in ChatGPT—Are you troubled by the thought, ‘I wish I had…’?”
With generative AI like ChatGPT becoming widespread, the use of AI in reports, papers, and written content is increasingly raising concerns.
If everything were created by AI, it would be difficult to assess student reports based on their actual academic knowledge. Similarly, if it becomes common knowledge that AI alone can earn a passing grade, it could undermine the credibility of education.
When AI-generated content is shared publicly, it may also affect a company’s reputation and, in some cases, lead to legal consequences.
This is why detection tools are essential. They help determine how much AI is involved in your text, reports, or papers.
This article provides an overview of AI detection tools, usage results, and a focus on tools that support Japanese, helping you verify content authenticity efficiently.
What Are the Detection Tools Available for ChatGPT?
Detection tools identify whether a text was created by generative AI. They analyze the structure, style, and patterns of AI-generated text and compare them to human writing.
These tools are crucial for:
- Ensuring text authenticity
- Avoiding plagiarism and copyright issues
- Maintaining credibility
For example, students’ reports written entirely by AI won’t reflect their knowledge. Similarly, AI content with outdated or incorrect information could harm a company’s reputation if published without review.
With generative AI producing highly accurate content, AI detection tool have become essential for verifying information authenticity.
Results of Using Detection Tools on ChatGPT Sentences
We tested detection tools using a “Linguistics Report” generated by ChatGPT (GPT-5). The results below show how these tools judged the AI-generated text:
Japanese report results:
| Tool Name | AI Judgment |
| CudekAI AI Detector | 99–100% |
| Undetectable AI | 99% |
| Copyleaks | 100% |
| GPTZero | 99% |
| isgen.ai | 100% |
| Smodin | 80% |
English translation results:
| Tool Name | AI Judgment |
| Originality.ai | 100% |
| Crossplag | 88% |
| ZeroGPT | 96.15% |
| Winston AI | 100% |
| Sapling AI Detector | 100% |
| KAZAN SEO | 10.44% |
These results show that even translated text generated by ChatGPT is reliably detected as AI-written.
6 Tools to Detect Text Written with ChatGPT
CudekAI AI Detector
CudekAI AI Detector is a free, highly accurate AI detection tool that identifies text written by AI or humans. It supports major AI platforms including ChatGPT, Google Gemini, Claude, and Copilot.
Key Features:
- Supports 100+ languages, ideal for global users and non-native English writers
- Sentence-level analysis, highlighting AI-generated parts
- Quick, precise results with high accuracy
- No signup required; upload text or documents directly
- Trusted by professionals: writers, educators, publishers, and researchers
Undetectable AI
Supports over 19 million users. Input up to 10,000 characters per check. Can detect AI-written text and rewrite it to appear human-like. Free usage does not require registration; paid plans increase character limits and add features.
Copyleaks
Covers the latest AI models with 99%+ accuracy. Detects AI content, checks plagiarism, and helps make text more human-like. Free accounts support basic use; paid plans expand credits and allow more comprehensive checks.
GPTZero
Supports up to 5,000 characters per input. Offers a simple, easy-to-read interface and multilingual detection (English, French, Spanish, Japanese). Free use requires no registration; premium plans allow larger word limits and more detailed checks.
isgen.ai
Allows up to 12,000 characters per month. Minimalist interface ideal for users who want AI detection only. Paid plans increase limits and provide detailed analysis.
Smodin
Supports 5,000 characters per input. Offers AI detection, rewriting, plagiarism checks, and AI text creation. Free usage is limited to twice a week; paid plans increase usage and add features like summarization and translation.
[Caution] The Judgment of the Detection Tool is Not Absolute
Detection tools are highly accurate but not infallible. AI-like sentence patterns can cause human-written text to be flagged as AI-generated, especially for non-native English writers. Conversely, AI text edited by humans may appear “human-written.”
Always treat AI detection results as supportive information, not absolute judgment.
How to Distinguish Sentences Created With ChatGPT
The most reliable method is to use detection tools along with human review. Key characteristics of AI-generated text:
- Consistent and logical flow
- Avoids the repetition of the same words unnaturally
- Uses uncommon or advanced words
- Uniform writing style and structure
- Lacks personal opinions or feelings
- May include outdated information
Do You Have Personal Opinions or Feelings?
AI rarely expresses personal opinions. For example, class reports created by AI are often superficial and lack genuine insights. Checking for authorial opinions is a clear indicator of human writing.
Flow and Structure of the Text
AI often follows repetitive structures like “Conclusion → Example → Summary” across sections. Repeated patterns may indicate AI authorship, though humans can also mimic similar structures.
Use Detection Tools to Check Your AI Writing
Detection tools like the CudekAI AI Detector help verify if content was created by AI. In our tests, GPT-5 text was consistently flagged as AI-generated, showing high detection accuracy.
However, tools are not absolute. AI-edited text may appear human, and some human writing may be flagged as AI.
Use detection tools as a supportive aid, combined with human judgment, for effective verification.
Conclusion
Using AI detection tools is essential in today’s world of generative AI. CudekAI AI Detector stands out as the most accurate, multilingual, and easy-to-use solution, making it the top choice for anyone verifying AI-generated content.