What is Gunning Fog Index Calculator?
Gunning Fog Index Calculator — The Gunning Fog Index estimates the years of formal education a reader needs to understand a text on first reading: Fog = 0.4 × [(words ÷ sentences) + 100 × (complex words ÷ words)], where complex words have three or more syllables.
Robert Gunning was a newspaper consultant who, in 1952, gave editors a number for what they already knew: long sentences stuffed with long words lose readers — 'fog'. His index is the bluntest of the classic formulas and the one most sensitive to polysyllabic jargon, because complex words are half of the entire score. That makes it the right lens for business, legal, and marketing copy, where three-syllable habit words ('utilize', 'implement', 'functionality') do most of the damage. The analyzer counts them for you; the sections below explain the counting rules and how to actually lower the score.