Readability checker
Paste your article, blog post, or documentation to analyze its readability and school grade level. The tool calculates Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, Automated Readability Index (ARI), Coleman-Liau, and provides detailed metrics on words per sentence, syllable counts, and reading time.
Calculates client-side · Text never leaves your device
Fairly Difficult (10th–12th grade)
High school level. Typical of business reports and technical tutorials.
9th Grade (High school)
US school grade level required to comfortably read this text on first pass.
Additional Reading Formulas
Gunning Fog Index
11.3
Standard audience
Automated Readability (ARI)
11.2
Approx. grade 11
Coleman-Liau Index
13.3
Letter & sentence based index
Text Structure & Content Statistics
Words
95
Sentences
7
Syllables
156
Paragraphs
3
Words / Sentence
13.6
Syllables / Word
1.64
Complex Words (3+ syl)
14 (14.7%)
Characters (w/ spaces)
618
Characters (no spaces)
522
Est. Reading Time
~0.4 min
Est. Speaking Time
~0.7 min
Example
Standard blog post readability
A 300-word article with 15 words per sentence and 1.4 syllables per word scores ~68 on Flesch Reading Ease (Standard / Plain English, suited for an 8th-grade reading level), with an estimated reading time of 1.3 minutes.
Related: Text diff checker, Case converter
FAQ
- Does this readability checker send text to external APIs or LLMs?
- No. Readability scoring uses deterministic linguistic formulas running 100% in your browser. No text is sent to any server, third-party API, or AI model.
- What is a good Flesch Reading Ease score?
- For general web content, consumer products, and public guides, a score between 60 and 70 (Standard / Plain English) is recommended. Scores between 70 and 80 are easy to read (7th grade level). Scores below 50 reflect dense academic, technical, or legal prose.
- How does the Flesch-Kincaid Grade Level formula work?
- The formula is: 0.39 × (total words ÷ total sentences) + 11.8 × (total syllables ÷ total words) − 15.59. It indicates the number of years of formal education in the US school system typically required to understand the passage.
- What counts as a complex word in readability formulas?
- In the Gunning Fog Index and related metrics, words with three or more syllables (excluding common suffixes like -es, -ed, and -ing) are classified as complex or polysyllabic words.
- How do I calculate Flesch Reading Ease without this page?
- Tokenize text into words (regex /[^a-zA-Z0-9_-]+/) and sentences (split on [.!?]+ followed by whitespace, protecting common abbreviations like Mr. and Dr.). For each word, count syllables by matching vowel clusters [aeiouy]+, deducting silent trailing 'e' and non-t/d 'ed' endings, and adding 1 for consonant+'-le' endings (minimum 1 syllable per word). Compute avgWordsPerSentence = words / sentences and avgSyllablesPerWord = syllables / words. Flesch Reading Ease = 206.835 - 1.015 * avgWordsPerSentence - 84.6 * avgSyllablesPerWord. Clamp score to 0..100. Flesch-Kincaid Grade = 0.39 * avgWordsPerSentence + 11.8 * avgSyllablesPerWord - 15.59.