Readability formula

A mathematical formula that estimates the difficulty of reading a text, typically based on features like sentence length, word length, syllable count, or vocabulary frequency. Common formulas include Flesch Reading Ease, Flesch-Kincaid Grade Level, SMOG, and Gunning Fog Index. In accessibility work, readability formulas help evaluate whether content meets the needs of target audiences such as people with cognitive disabilities, low literacy readers, or non-native speakers. While useful for automated assessment, these formulas have limitations—they measure surface-level text features rather than conceptual complexity, coherence, or comprehensibility for specific disability groups.