Analyze text readability using Flesch-Kincaid and other readability formulas. Get grade level and score.
The Readability Score Checker analyzes your text using the Flesch Reading Ease scale, Flesch-Kincaid Grade Level and Gunning Fog Index to give you an objective measure of how easy your writing is to understand. It also reports word count, sentence count, syllable count, average word length and average sentence length. Writers, marketers, educators and UX professionals use it to ensure content matches the reading level of their audience.
The Flesch Reading Ease formula is: 206.835 - (1.015 x average sentence length) - (84.6 x average syllables per word). Scores range from 0 to 100 - higher scores mean easier reading. A score of 60-70 corresponds to standard newspaper prose (8th-9th grade level), while scores below 30 indicate highly technical or academic writing. The syllable count is estimated algorithmically using vowel-cluster detection, which is accurate for most English words but may slightly miscount unusual proper nouns or foreign words.
No. All readability calculations happen entirely in your browser using JavaScript - no text is transmitted to any server, stored or logged. You can safely analyze confidential business writing, unpublished manuscripts or private communications. The results exist only in your current browser session.
Both metrics estimate U.S. school grade level required to understand a text, but they use different approaches. The Flesch-Kincaid Grade Level is based on average sentence length and average syllables per word, similar to the Reading Ease formula. The Gunning Fog Index instead counts "complex words" - words with three or more syllables - alongside average sentence length, making it more sensitive to jargon and technical vocabulary. For general content, both scores tend to agree closely; they diverge when texts have short sentences but many polysyllabic terms.
The tool requires at least 20 characters before displaying results, but for statistically meaningful readability scores you should analyze at least 100 words (ideally 200+). Very short texts of one or two sentences produce unreliable scores because a single unusually long or short sentence heavily skews the averages. For best results, paste a representative paragraph or the full article rather than a single headline or bullet point.
Hemingway App and Grammarly provide inline highlighting and sentence-level suggestions on top of readability scoring, making them better for active editing workflows. This tool focuses purely on quantitative metrics - Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index and supporting statistics - in a fast, zero-signup, privacy-first environment. It is the better choice when you need a quick objective score without sending your text to a third-party cloud service or subscribing to a paid plan.