ATOS Analyzer vs Delimiter Readability Checker

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.

Delimiter Readability Checker is a free web tool that scores English text with Flesch Reading Ease, Flesch–Kincaid Grade, and Gunning Fog formulas. It shows sentence and syllable averages behind the scores, updates results automatically in the browser, and does not send entered text to a server. A Load file control accepts text, and a Copy control copies results. The page suggests checking public-facing copy, plain-English requirements, long articles, and draft rewrites. It includes sentence analysis and clarity recommendations, and no account is required. The formulas were calibrated on English prose, so scores for other languages are not meaningful. They assess sentence and word length rather than clarity, accuracy, or structure. Syllable counting is heuristic, so individual words may be counted incorrectly. The tool has a free plan at free, with no paywall. Support is available at [email protected], although replies are not instant and no response time is promised.