Glossary
Every readability formula, explained in plain English.
Flesch Reading Ease
A 0–100 score where higher means easier to read. 60–70 is plain English.
Flesch-Kincaid Grade Level
A US grade-level score. 8.0 means a typical 8th-grader can read it.
Gunning Fog Index
A grade-level score tuned for business writing. Penalizes multi-syllable jargon.
SMOG Index
A grade-level formula designed for healthcare and safety content. Requires 30+ sentences.
Coleman-Liau Index
A grade-level formula based on characters, not syllables. Good for OCR and machine analysis.
Automated Readability Index (ARI)
A character-count grade score designed for electronic typewriters in 1967.
Linsear Write
A formula built inside the US Air Force to evaluate technical manuals.
Fernández-Huerta (Spanish Flesch)
The Spanish-language adaptation of Flesch Reading Ease. Same 0–100 scale.