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How to use Ludwig AI Detector
Step 1
Scan: Paste your text* into the AI Detector and press the “Scan” button at the bottom of the tool.
Step 2
Receive results: Get a total score** with an highlighting showing which sentences are most likely AI-generated.
Step 3
Edit: Modify the highest AI scoring sentences.
Re-scan: You are free to re-run the scan until you’re satisfied.
* Check length: Make sure your text is at least 350 characters. For documents longer than 10k chars, use the Editor. ** The score is expressed with a % and indicates how confident our AI Detector is that the content scanned was produced by an AI tool.
Ethical AI:
Promoting integrity and fairness
We believe condemning AI is discriminatory—especially for non-native speakers who use it to bridge linguistic gaps. Checking grammar or rewriting a clunky sentence with AI is no different from using a dictionary.
When AI detection goes wrong, careers get damaged and students fail assignments they did honestly. We're not naive: AI can be misused. But condemning the tool itself misses the point.
We believe in good, original ideas—even when polished with AI.
Our detector helps you make informed decisions. And perhaps a tool that circumvents unfair systems is a tool of freedom.
An AI checker for all needs
TEACHERS
STUDENTS
BUSINESS
WEB WRITERS
EDITORS
There's a huge difference between AI-generated and AI-refined texts. Discover whether your students' homework is done only with the help of AI or is completely AI-generated. By detecting AI writing with our tool, you will make better informed decisions about the originality of your students' works. Check it out for free!
Our AI detection technology
Ludwig's AI detector uses an ensemble voting mechanism of fine-tuned BERT and RoBERTa models, trained via supervised learning on ~1 million documents—both human-written (from public sources) and AI-generated (including from the newest models like GPT-5).
The system analyzes features such as perplexity (how predictable the text is to an LLM) and burstiness (variation in linguistic patterns like sentence structure and word choice) to identify AI-generated writing.
Subsequent training iterations focus on minimizing false positives and improving robustness against paraphrasing and humanization techniques.
>99% accuracy rate
>99% accuracy rate at detecting AI content (the rate at which AI content is correctly flagged as AI).
<0.5% false positive rate
<0.5% false positive rate (the rate at which human documents are incorrectly flagged as AI).
Light AI editing
Light AI editing (grammar check and some paraphrasing) will not result in a false positive.
Against humanizing
Our detection software is extremely robust against humanizing methods.
Native desktop power, universal integration
Get the Ludwig experience without switching tabs, by downloading the desktop app. It works perfectly with all your favorite writing apps, too!
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Why you should go Ludwig Premium
Free
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Limited text per scan
~1 page worth of text
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Limited number of daily scans
Perfect for testing
Premium
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Maximum text per per scan
3+ pages worth of text
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Unlimited* daily scans
Perfect for writers, students, teachers and editors
*Unlimited access is subject to abuse guardrails.
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Trusted by 2 million users worldwide
Ludwig is by far the best website to check your language to find examples in prominent papers. I am a language teacher and an author, and with the help of Ludwig, I can ensure what I'm teaching is authentic and, more importantly, reliable!
IELTS Go pro
I have been very pleased with Ludwig.guru application from the start, it definitely helped me both in academic and professional environments. I would absolutely recommend Ludwig.guru to anyone who wants to achieve that next level of writing style, seek to improve one's writing skills and/or enhance one's writing ability.
Pete
The app service is practical and very intuitive. It has greatly helped me during the writing of my scientific articles and even long my phD thesis. Thanks to Ludwig, I fixed some style mistakes, and it provided me with several good suggestions. I recommend it!
Alessandro
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Frequently Asked Questions
How does your AI Detector work?
Ludwig's AI Detector provides a percentage score that reflects how much of the submitted text looks like AI content, based on its AI model.
The model is trained on extensive datasets containing both human-made text and AI writing. It analyzes the text in smaller sections, identifying patterns typical of AI-generated language. Each section is evaluated, and the tool aggregates the results into a single percentage score.
The AI checker is built to assess how much your texts resemble AI-generated writings; however, no AI content detector on the web is capable of performing this task with a 100% reliability rate.
Please beware of AI checker and plagiarism checker platforms that claim otherwise. The best way to get a fact-checker, readability checker, and grammar checker all in one is to use all the AI writing tools on Ludwig's platform.
Ludwig is a comprehensive writing platform that allows you to paraphrase and use our sentence rewrite tool for free after signing up. Combat plagiarism and rewrite sentences with originality and clarity.
Ludwig's AI Detector features a precision rate of 99.6% when checking for AI, focusing on accuracy to avoid false positives. It uses advanced algorithms to analyze perplexity, sentence patterns, uniformity, semantic normality, coherence, and so on.
How can Ludwig's AI checker help me publish with integrity?
Checking for machine-generated texts or parts of text with AI Detector can help reword phrases that some AIs might have copied from other original works. This is why Ludwig's AI Detector can be a useful ally for plagiarism checks.
Get the percentage of AI writing in your text, with highlights on the most critical phrases or parts of the text that need rewording, paraphrasing, or a readability check.
If your AI score is still too high, remember that Ludwig is not just an AI content detector: you can rewrite your sentence using Ludwig's rephrasing tool (Rewrite) or Editor for longer texts that need a grammar checker, paraphraser, and readability checker altogether.
In fact, if you need an essay checker, a grammar check of an entire paper, or a thorough edit of longer texts, you can rework your entire text at once in Ludwig's Editor, the space for editing, checking, and rephrasing texts longer than 260 characters.
Does Ludwig handle long-form content?
Ludwig supports analyzing up to 2,800 characters for each AI check for free. Register to use AI Detector for free up to five times/day! Do you need more? You can get 5,000 characters per query with Premium, and up to 10,000 characters per query with Premium Plus.
Be aware that the longer the text is, the easier it is for AI Detector to achieve accuracy in detecting AI. This is because the longer the text a machine generates, the higher the possibility of falling into hallucinations and repetitions, two factors that AI Detectors keep in high regard when scanning for AI.
In fact, Ludwig AI Detector asks you to provide it with a text long at least 500 characters, the minimum necessary to grant a reliability rate that is worth its name. This makes it the perfect essay checker for AI writing.
Can Ludwig detect ChatGPT writing?
Yes, Ludwig detects ChatGPT writing with accuracy. But AI Detector is not just a GPT checker, it also checks for AI models like Llama, GPT-4, GPT-5, Claude, and Gemini. "One AI checker to rule them all," one may say. Detector can function properly as a plagiarism checker.
Is Ludwig's AI Detector free?
Register and use AI Detector for free five times a day. If you need more, our Premium and Premium Plus plans offer AI Detector–and all Ludwig's tools included–for a reasonable fee, billable monthly or annually.
Check out our plans and their features in detail at this page.
Ludwig offers a vast array of high-quality paraphrasing options at the most competitive price-for-value rate on the market.
What is Ludwig's approach to minimizing false positives?
Ludwig prioritizes precision over excessive flagging, ensuring that content marked as AI-generated has a very high likelihood of being accurate. This approach reduces unnecessary false positives, as we believe that it's better to mark something AI-generated as human-looking, rather than having something written by humans marked unjustly as machine-generated.
What does "Unlimited" usage mean?
Premium users can use Ludwig AI Chat without limitations. There are some guardrails in place to prevent abuses and to allow all users access the service effectively. Usage must adhere to our Terms of Use, which prohibits, among other things:
• Abusive usage, such as automatically or programmatically extracting data.
• Sharing your account credentials or making your account available to anyone else.
• Reselling access or using Ludwig Premium to power third-party services.
To prevent misuse, we have guardrails in place and are always working to improve our systems. This may occasionally involve a temporary restriction on your usage. We will inform you when this happens, and if you think this might be a mistake, please don't hesitate to reach out to our support team at support@ludwig.guru from the support button in the menu. If policy-violating behavior is not found, your access will be restored.