Compute Flesch-Kincaid, Gunning Fog, Coleman-Liau, SMOG

Calculate several published English readability formulas from the same text statistics.

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ToolReadability Score
Input
Output
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How it works

Words, punctuation-delimited sentences, letters, and estimated English syllables are substituted into Flesch Reading Ease, Flesch-Kincaid, Gunning Fog, Coleman-Liau, and ARI. SMOG appears only for samples of at least 30 sentences, and the results remain separate rather than being averaged into a fictional grade.

  • Syllables are estimated from spelling, so English exceptions make the figures approximate.

Worked example

Analyze article readability
Compare published readability formulas for a paragraph
Input
											The cat sat on the mat. It was a warm day. The sun was shining brightly in the clear blue sky.
Output
												Flesch kincaid grade: 0.1
Gunning fog: 2.8
Coleman liau: -0.4
Automated readability: -2.6
Smog: unavailable (fewer than 30 sentences)

FLESCH READING EASE
Score: 100
Level: Very Easy (5th grade)

STATS
Words: 21
Sentences: 3
Syllables: 23
Complex words: 0

When to use this

Plain-language reviews, instruction manuals, and editorial revisions compare formula results with the intended audience.

Edge cases

  • A three-sentence paragraph leaves SMOG unavailable because its standard sample uses 30 sentences.
  • Queue can defeat a vowel-group syllable estimate.
  • An abbreviation such as e.g. can create a false sentence boundary.

References