Text Readability Score

A readability score is a numerical measure that indicates how easy or difficult a text is to read and understand. Different formulas calculate readability using factors like word length, sentence length, syllable count, and text complexity. Higher scores generally mean easier readability.

The Flesch Reading Ease score ranges from 0-100, where higher scores indicate easier text. A score of 90-100 is very easy (5th grade), 60-70 is standard (8th-9th grade), and below 30 is very difficult (college graduate level). This formula considers average sentence length and syllables per word.

The Flesch-Kincaid Grade Level translates readability into U.S. school grade levels. The formula uses average words per sentence and syllables per word. A score of 8.0 means an 8th grader can understand the text. It's widely used in education and government for document standards.

SMOG (Simple Measure of Gobbledygook) estimates the years of education needed to understand text. It focuses on complex words (3+ syllables) and requires at least 3 sentences for accuracy. It's particularly useful for health and medical documents.

The Coleman-Liau Index uses characters per word instead of syllables, making it easier to compute. It calculates readability based on the average number of letters per 100 words and sentences per 100 words. This makes it useful for automated text analysis.

ARI estimates the U.S. grade level needed to comprehend text using character counts and word counts rather than syllable counts. It was designed for real-time monitoring of readability on typewriters and is still widely used today for quick readability assessments.

Each formula has strengths for different contexts. Flesch Reading Ease is best for general content, Flesch-Kincaid for educational materials, SMOG for health/medical documents, Coleman-Liau for automated analysis, and ARI for technical writing. Using multiple formulas provides a comprehensive view.

Target readability depends on your audience. For general web content, aim for 8th-10th grade level (60-70 Flesch score). Academic papers may be 12th grade+, while marketing content should be 6th-8th grade. News articles typically target 8th grade, and legal documents often score at college level or higher.

To improve readability: use shorter sentences (15-20 words), choose simple words over complex ones, avoid jargon unless necessary, break long paragraphs into smaller chunks, use active voice, and replace multi-syllable words with shorter alternatives. Each formula responds to different factors.

Different formulas emphasize different aspects of readability. Flesch focuses on syllables and sentences, SMOG on complex words, Coleman-Liau on characters, and ARI on character-to-word ratios. Variations are normal and provide different perspectives on text complexity.

Yes! Search engines favor content that matches user reading levels. Most web users read at 8th-10th grade level, so targeting Flesch scores of 60-70 improves engagement and SEO. Readable content reduces bounce rates and increases time on page, both positive SEO signals.

These formulas were designed for English text and may not be accurate for other languages. Different languages have varying syllable patterns, word lengths, and sentence structures. For non-English text, use language-specific readability formulas if available.

Most formulas work with any amount of text, but SMOG Index requires at least 3 sentences. For the most accurate results across all formulas, analyze passages of at least 100 words with 5+ sentences. Longer texts (300+ words) provide more reliable readability scores.

No, all readability calculations happen entirely in your browser using client-side JavaScript. Your text is never sent to servers, stored in databases, or shared with third parties. Your content remains completely private and secure.