Free Readability Score Calculator Online — No Signup Required

Readability scores measure how easy a piece of text is to read, based on sentence length and word complexity. The most widely used formulas are Flesch-Kincaid Reading Ease (0–100 scale, higher is easier), Flesch-Kincaid Grade Level (US school grade level), Gunning Fog Index (years of education to understand), and SMOG Index (reading level based on polysyllabic word count). Web content aimed at a general audience should target a Flesch Reading Ease of 60–70 (equivalent to 7th–8th grade level) for maximum accessibility.

Content readability affects both user engagement and SEO. Difficult-to-read content has higher bounce rates because readers abandon text they struggle with. Google's quality evaluator guidelines (used by human quality raters) include readability as a factor in assessing content quality. This tool scores your text against multiple readability formulas, highlights sentences that are too long, identifies complex polysyllabic words, and shows average sentence and word length — giving you specific targets for simplifying your writing.