Free AI Detector and AI Checker

AI detectors use machine learning models to recognize patterns that distinguish AI-generated content from human writing. These models are trained on large datasets containing both AI- and human-written text, allowing them to identify key differences in style, structure, and predictability.



To estimate whether a text was AI-generated, AI detectors analyze several characteristics:

• Sentence structure and predictability: AI-generated text often follows consistent patterns, whereas human writing tends to be more varied and unpredictable.
  
• Repetition and uniformity: AI models frequently repeat phrases, while human writers naturally introduce more variation.
  
• Metadata traces: Some AI tools embed hidden markers in their output, which detection models can identify.
  
• Comparison with known AI outputs: Some detectors compare text to a database of known AI-generated content. This method is less effective for advanced AI models that can generate highly varied outputs.
  

Using Grammarly’s free AI detector is simple:

1. Paste your text or upload a document into the tool at the top of this page.
   
2. Click Scan for AI.
   
3. In seconds, you’ll see what percentage of your text appears to be AI-generated.
   

When you sign up for Grammarly Pro, you get access to the AI Detector agent, which goes beyond a score. It helps you see exactly which parts may sound AI-generated, refine them in real time, and add properly formatted citations without breaking your writing flow.


Learn more about how AI detectors work here.

While AI detectors can help assess whether text appears to be AI-generated, currently there is no AI detector that can conclusively or definitively determine whether AI was used to produce text. That’s because the accuracy of these tools can vary based on the algorithms used and the specific characteristics of the text being analyzed. AI detection tools should be just one part of a holistic approach to evaluating writing originality.

No AI detector is 100% accurate. This means you should never rely on the results of an AI detector alone to determine whether AI was used to generate content. AI detectors can indicate characteristics found in human-written text as well as characteristics commonly found in AI-generated writing, such as language patterns that seem robotic or generic. But, they cannot definitively conclude whether or not AI was used. These tools should be one part of a holistic approach to evaluating writing originality.

Yes, Grammarly’s AI detector and other ChatGPT checkers can identify text produced by AI models like ChatGPT, Gemini, Claude, Microsoft Copilot, and more.

To learn more about all things AI, visit the Grammarly blog.

Your writing might be flagged for AI if it exhibits patterns, structures, or characteristics typical of text that has been created with generative AI. Learn more about why your writing may have been flagged on the Grammarly blog.

What is and is not considered cheating can be subjective—what one professor considers acceptable might be off-limits to another. It also varies based on the assignment and how you intend to use AI. When writing in an academic setting, always comply with your institution’s and educator’s AI usage policies, typically found in course syllabi or academic integrity guidelines. 

If you use AI, we recommend you disclose it with a citation. Grammarly can instantly generate citations for AI usage when you use generative AI tools. 

Grammarly’s AI detector is built to encourage thoughtful and responsible AI use. Writers can use it to get a gut check on how their content comes across and identify places where adding a more personal voice might strengthen their message. Readers, in turn, can use the detection results to better understand how a piece of writing may have been created.

When a document is scanned, Grammarly segments the text and analyzes each section for language patterns that are often linked to AI-generated writing. Our detection model was trained on tens of thousands of texts, including both human-written and AI-generated text created before 2021. This training enables it to recognize key differences between the two. Based on this analysis, Grammarly generates a percentage score estimating how much of the content may have been generated by AI.

To learn more, read our in-depth blog article on how AI detectors work.

No AI detector is 100% accurate—every tool has limitations. The most effective detectors are transparent about how they work, regularly updated, and used alongside other tools like plagiarism checks and authorship verification. Grammarly’s free AI detector and its AI Detector agent combine advanced machine learning with our long-standing expertise in writing assistance to deliver reliable results, helping you understand where AI may have influenced your text.

The best AI content detector is one that’s accurate, transparent, and designed for responsible use, not just one that promises perfect results. Because AI writing is evolving quickly, no detector can guarantee 100% accuracy. Grammarly’s free AI detector and its AI Detector agent are built with advanced machine learning and grounded in responsible AI practices. It gives you a clear score that shows how much of your work appears to be written with AI so you can submit it with peace of mind.

No AI detector is 100% accurate. AI detectors estimate the likelihood that the text was AI-generated. They do not track authorship, which means even human-written text can be flagged as AI-generated. Meanwhile, lightly edited AI-generated text may evade detection. As a result, AI detection should never be used as a standalone verification method.

If you’re using AI in your writing process, the goal shouldn’t be to hide it but to make sure the final result reflects your own thinking and voice. You can do this by adding personal examples, mixing up sentence length, rephrasing AI output in your own words, and adjusting the tone to match your natural style. Additionally, Grammarly’s features are designed to support transparency and responsible AI use so you can focus on creating content that reflects your own thinking and voice. Here’s how Grammarly supports you:

• AI detection lets you check how your writing sounds and see where you might want to add more of your personal voice.
  
• Plagiarism detection compares your work against online sources to make sure your writing is original and properly attributed.
  
• Citations help you easily and clearly acknowledge your sources—whether you’re referencing AI tools, websites, or other materials—making it easier to maintain transparency and meet academic or professional standards.
  
• Grammarly Authorship tracks how your text was created, giving you a clear record of how your work came together. This can be useful for proving originality and navigating questions about how your writing was developed.