ContentDetector.org vs GPTKit

ContentDetector.org is a free tool that estimates whether text was AI-written and reports a percentage split between AI-written and human-written content. Users can paste text, upload a file, or submit a URL for a report with a score, section highlights, and review guidance. The site says the detector evaluates token-pattern predictability, semantic repetition, formatting regularity, and local stretches of uniform phrasing, including patterns associated with GPT-5, Gemini, Claude, and other large models. It also offers a converter that rewrites AI-generated text to improve tone, flow, clarity, and sentence variety; the converter page shows a 1000-character input counter. Other listed options include API access and bulk checks of folders or URL lists. Platforms include web, extension, iOS, macOS, and Windows. The site says inputs are not used to train models and describes retention controls; its FAQ says inputs are removed when the tab is closed, while the converter page says submitted content is processed instantly and not stored. It warns results can be wrong, especially for very short or heavily edited text, and recommends human review.

GPTKit analyzes submitted text and classifies it as human-written or ChatGPT-generated. It is available through a web interface and an API, with English currently supported. The maker says the detector combines six AI-based methods, was trained on 1 million datasets, and produces authenticity and reality reports. GPTKit reports approximately 93% accuracy based on testing 100K+ human and ChatGPT responses. The first 2048 characters of every request are free, including for guests; the Free Plan allows up to five requests per minute. Unlimited (Personal) costs $5 a month and supports two team members. Unlimited (Team) costs $10 a month, supports eight members, and includes API access. Unlimited (Institution) costs $20 a month, supports 20 members, and includes API access. Team credits can be shared. GPTKit says submitted text is temporarily stored and removed after detection; its policy says absolute security cannot be guaranteed.