AI Detectors.io vs ClassGuard

AI Detectors.io analyzes text associated with major language models, returning an overall AI probability, confidence scores, and sentence-level results. The site also offers a humanizer, citation verification, plagiarism checking, grammar tools, and watermark removal. Its detector says it examines perplexity, burstiness, n-gram patterns, and stylometric fingerprints. The company reports 95.2% accuracy and 3.1% false positives from an April 2026 benchmark of 500 texts. The detector is trained and benchmarked on English; it returns scores for other languages, but those languages are outside that benchmark. Access is available through the web, Chrome extension, Microsoft Word add-in, and REST API. The Word add-in supports Word 2016 and later on Windows and Mac, as well as Word for the web, and can produce PDF reports. The free plan includes 10,000 words per month and a 500-word-per-use limit. Premium is listed at $8.33 a month, billed annually, with scans up to 25,000 words. Submitted text may be processed by third-party providers and retained as long as needed to support the service.

ClassGuard has no write-up on Specifiction yet; its figures are above.