ATOS Analyzer vs Data·yze Readability Analyzer

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.

Data·yze Readability Analyzer is a free, ad-supported web app that estimates how readable text may be for a chosen audience. It reports Flesch-Kincaid Reading Ease, Gunning Fog Index, Kincaid Grade Level, SMOG, Dale–Chall, and Fry Reading Graph metrics. Sentence analysis and clarity recommendations are available, while a paragraph view shows statistics and changes in readability through a document. You can enter text or upload a file, then save or download the input. A separate Website Readability Analyzer evaluates an individual webpage and average readability across a site. Its crawler is limited to 1,000 pages per user per day; pausing and resuming on another day can work around that cap. Data·yze says analyzed passages are not collected or stored, although passage length is retained for performance analysis. Uploaded files may be cached and automatically removed within seven days, possibly sooner. The maker cautions that scores are heuristic estimates, not writing-quality measures, and work best with plain text.