Coleman-Liau Index
A grade-level formula based on characters, not syllables. Good for OCR and machine analysis.
Coleman-Liau was developed in 1975 by Meri Coleman and T.L. Liau. Unlike Flesch-based formulas, it doesn't count syllables — only characters and sentences. 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. This makes Coleman-Liau ideal for computer-based analysis since syllable counting is error-prone. It tends to score non-English-style text more fairly, though the grade labels are still US-centric.