ATOS Analyzer vs Readability Formulas

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.

Readability Formulas offers tools to score English text and estimate the grade level and age of readers likely to understand it. Its Readability Scoring System includes formulas such as Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, SMOG, Dale-Chall, Spache, FORCAST, Fry and Raygor. Text can be pasted or supplied as .txt, .docx, .rtf, .html or .pdf files. Text Statistics reports measures including syllable count, average sentence length, abbreviations, proper nouns and passive voice. The beta Robert Gunning Editor helps locate difficult words and wordiness, with editing tools for phrases, nominalizations, fuzzy words and weak verbs. Batch Processing, also in beta, scores multiple texts with one or more formulas. A Chrome and Microsoft Edge extension can score highlighted web text, open the editor and show word statistics. The privacy policy says processing runs through local browser scripts and submitted text is not stored on a server or accessible to the site. The Synonym Finder connects to Datamuse and may transmit one word at a time.