Readability Score Checker

Analyze your text's readability using five proven formulas. Get grade levels, audience recommendations, and actionable tips.

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Understanding Readability Scores

Flesch Reading Ease (0—100)

Developed by Rudolf Flesch, this score rates text from 0 (very difficult) to 100 (very easy). Formula: 206.835 - 1.015 — (words/sentences) - 84.6 — (syllables/words)

90—100: Very easy (5th grade) — Comics, simple instructions
80—89: Easy (6th grade) — Conversational English
70—79: Fairly easy (7th grade) — Consumer magazines
60—69: Standard (8th—9th grade) — News articles, most web content
50—59: Fairly difficult (10th—12th grade) — Business writing
30—49: Difficult (College) — Academic papers
0—29: Very confusing (College graduate) — Legal, scientific texts

Flesch-Kincaid Grade Level

Translates the Flesch score into a U.S. school grade level. Formula: 0.39 — (words/sentences) + 11.8 — (syllables/words) - 15.59

Gunning Fog Index

Estimates the years of formal education needed. It penalizes complex words (3+ syllables). Formula: 0.4 — ((words/sentences) + 100 — (complex words/words))

Coleman-Liau Index

Uses character counts instead of syllables, making it more mechanical. Formula: 0.0588 — L - 0.296 — S - 15.8 where L is average letters per 100 words and S is average sentences per 100 words.

Automated Readability Index (ARI)

Uses characters per word and words per sentence. Formula: 4.71 — (characters/words) + 0.5 — (words/sentences) - 21.43

Frequently Asked Questions

The tool applies five established readability formulas to your text: Flesch Reading Ease, Flesch-Kincaid Grade Level, Gunning Fog Index, Coleman-Liau Index, and Automated Readability Index. Each formula measures different aspects like sentence length, syllable count, and word complexity to produce a readability score and grade level.

Yes. All readability analysis happens 100% client-side in your browser using JavaScript. Your text is never sent to any server, stored, or shared with anyone. You can safely analyze confidential documents, academic papers, or business content.

Flesch Reading Ease scores range from 0 to 100. A score of 60—70 is considered ideal for general web content and is easily understood by most adults. Scores above 70 are very easy to read, while scores below 30 indicate very complex, academic-level text. For broad public communication, aim for 60 or higher.

Each formula has its strengths. Flesch Reading Ease is the most widely used and easy to understand. Flesch-Kincaid Grade Level maps directly to US school grades. Gunning Fog focuses on complex words. Coleman-Liau uses character counts and is more mechanical. The tool shows all five so you can get a comprehensive view of your text's readability.

The readability formulas were designed for English text and rely on English syllable counting and sentence structure. While the tool will process non-English text, the scores may not be accurate because syllable patterns and sentence structures differ across languages. For best results, use it with English content.

Readability Score Checker

Audience Recommendation