Readability Calculator
Score how easy a passage is to read with Flesch Reading Ease, Flesch–Kincaid Grade, Gunning Fog and Coleman–Liau, plus full word, sentence and syllable counts.
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What this tool does
Score how easy a passage is to read with Flesch Reading Ease, Flesch–Kincaid Grade, Gunning Fog and Coleman–Liau, plus full word, sentence and syllable counts. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
How to use the Readability Calculator
- Enter or select text to score.
- Read the calculated result; change any measurement to compare alternatives.
Formula
Flesch Reading Ease = 206.835 − 1.015×(words/sentences) − 84.6×(syllables/words). Flesch–Kincaid Grade = 0.39×(words/sentences) + 11.8×(syllables/words) − 15.59. Gunning Fog = 0.4×[(words/sentences) + 100×(complex words/words)], where complex words have 3+ syllables. Coleman–Liau = 0.0588×L − 0.296×S − 15.8, where L = letters per 100 words and S = sentences per 100 words.
- text
- Text to score
Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
Worked example
For readability calculator, the following measurements illustrate the exact method: Text to score: Good writing is clear and simple. Short sentences help readers follow each idea. When writers choose common words, more people can understand the message the first time they read it..
Inputs
- Text to scoreGood writing is clear and simple. Short sentences help readers follow each idea. When writers choose common words, more people can understand the message the first time they read it.
Result
- Flesch Reading Ease75.43
- Flesch–Kincaid Grade5.22
- Gunning Fog Index6.67
- Coleman–Liau Index10.44
- Words30
- Sentences3
- Syllables43
- Characters (letters)149
- Complex words (3+ syllables)2
- Average words per sentence10
- Average syllables per word1.43
Results explained
- Flesch Reading Ease
- Flesch Reading Ease from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Flesch–Kincaid Grade
- Flesch–Kincaid Grade from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Gunning Fog Index
- Gunning Fog Index from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Coleman–Liau Index
- Coleman–Liau Index from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Words
- Words from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Sentences
- Sentences from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Syllables
- Syllables from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Characters (letters)
- Characters (letters) from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Complex words (3+ syllables)
- Complex words (3+ syllables) from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Average words per sentence
- Average words per sentence from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
- Average syllables per word
- Average syllables per word from the formula above. Syllables are counted with the standard vowel-group heuristic (silent trailing 'e' removed, minimum one per word), so unusual names and technical terms can be off by a syllable. Scores are guides to surface difficulty — sentence length and word length — not measures of quality or correctness.
Frequently asked questions
60–70 is plain English that most adults read comfortably, and most web and marketing copy aims for 60+. Scores of 80–90 suit younger or general audiences; below 50 the text reads as academic or professional, and below 30 as dense and specialist.
Flesch–Kincaid, Gunning Fog and Coleman–Liau each estimate the US school grade needed to understand the text on a first reading. A grade of 8 means a typical 13–14-year-old can follow it. The three formulas weight sentence length, syllables and characters differently, so they rarely agree exactly.
Shorten sentences — splitting one long sentence is the single biggest lever — and swap long words for shorter synonyms where meaning allows (use instead of utilise, help instead of assistance). Then re-score and check the passage still says what you meant.
Flesch and Flesch–Kincaid count syllables, Gunning Fog counts only words of 3+ syllables, and Coleman–Liau counts characters instead of syllables, which makes it sensitive to long but simple words. Reporting all four gives a range rather than false precision from one formula.
By the standard heuristic: count groups of consecutive vowels (y included), subtract one for a silent trailing 'e' (but not after 'le'), with a minimum of one syllable per word. It matches dictionary counts for most everyday words.
Yes. The passage is analysed entirely in your browser — it is never uploaded, stored or sent anywhere, so unpublished drafts are safe to score.