Text Readability Analyzer
Analyze any text with six standard readability formulas including Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and ARI.
Readability profile (grade level)
How It Works
Paste or type any text into the input. The tool tokenizes the text into sentences, words, and syllables, then computes six widely-used readability scores: Flesch Reading Ease (higher means easier, Rudolf Flesch 1948), Flesch-Kincaid Grade Level (U.S. school grade, developed for the U.S. Navy in 1975), Gunning Fog Index (weights complex words), SMOG Index (Simple Measure of Gobbledygook, McLaughlin 1969), Coleman-Liau Index (character-based, no syllable counting), and Automated Readability Index (character-based like Coleman-Liau, developed for the U.S. Air Force in 1967). Supporting statistics are shown alongside: word count, sentence count, average sentence length, average syllables per word, count of polysyllabic words (3+ syllables), and estimated reading time. The syllable counter uses a pronunciation-rule heuristic that handles common silent-e and vowel-cluster patterns. Everything runs instantly in your browser as you type.
Worked Example
Paste a 40-word contract sentence and the Flesch Reading Ease score sinks toward the unreadable end with a college-graduate grade level. Split it into three short sentences, swap the latinate verbs for plain ones, and re-analyse: the score climbs dramatically and the grade level drops to ordinary prose. Six established formulas — Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, ARI and more — score the same text from different angles, and the per-metric cards show which factor (sentence length versus word complexity) is dragging you down.
Use Cases
- Checking that a blog post, landing page, or email hits the target reading grade for its audience
- Simplifying technical documentation by iterating on wording until Flesch-Kincaid drops by a grade or two
- Meeting plain-language requirements for government, healthcare, or legal communications
- Comparing draft versions of a school essay against required grade levels
- Teaching writing students how different readability formulas emphasize different aspects of complexity
Frequently Asked Questions
- Which score is the most reliable?
- None alone — that is why six are computed. Flesch-Kincaid Grade and Coleman-Liau give the most consistent results for English prose. Compare two or three to triangulate.
- Why are syllable counts approximate?
- English syllable counting is heuristic — there is no exact algorithm without a pronunciation dictionary. The tool uses a vowel-cluster heuristic accurate within about ±10% of true counts on typical prose.
- What grade level should I aim for?
- For broad public communication, target Flesch-Kincaid Grade 8 or below. Government plain-language guidance often targets Grade 6–8. Technical documentation routinely sits at 12+.
- Does it work on non-English text?
- The formulas were calibrated on English. They produce a number for any text but the result is meaningful only for English-language input.
- Is my text sent anywhere?
- No. Tokenisation and scoring run entirely in your browser.