ATOS Analyzer vs ProWritingAid

ATOS Analyzer is a free web tool for estimating the readability level of text and books in English or Spanish. Users can enter a passage, analyze an entire book, or submit a sample with an estimated word count. Text can be typed or uploaded as a .txt, .docx, or .epub file, with uploads limited to 10 MB. The suggested passage length is 150 to 25,000 characters. Results include an ATOS level, grade-level equivalent, word count, AR Points, average word length, average sentence length, and language. ATOS estimates complexity on a grade-level scale using sentence length, word length, and word difficulty; its measure also accounts for book length. For a sampled book, Renaissance recommends three passages of about 150 words from different parts and an estimated total word count. Scanned documents need OCR to become recognized text before submission; changing a file extension does not convert them. The page includes a CCSS/ATOS grade-band chart for grades 1 through 12. Renaissance presents the measure as guidance for matching students with appropriately leveled reading material.

ProWritingAid provides grammar and style suggestions through browser extensions and a desktop editor. It works with Word, Google Docs, Scrivener, Chrome, Firefox, and Edge, and browser extensions are available for Chrome, Firefox, and Edge. The free account handles 500 words at a time and includes two line-editing runs, ten rephrases, three Sparks, and three Creative Nudges per day. Premium and Premium Pro support documents of any length. Premium includes document sharing, real-time comments, and more than 25 writing analysis reports. Its plagiarism checker compares work against webpages, published works, and academic papers. The product supports English only, including general, British, US, Australian, and Canadian English. ProWritingAid says text entered into its editor is not kept on processing servers, is encrypted during processing, and is not used to train algorithms. The free plan is available; listed paid plans include Premium at $30 a month and Premium Pro at $36 a month, both billed monthly.