Estimate the readability of text with the Gunning Fog Index.
The Fog Index combines average sentence length with the share of multi-syllable words, returning a rough school grade for the passage. A score below 8 is conversational while above 12 grows demanding. A high fog index flags prose that packs too many long words and long sentences, which drives readers away from dense documents.
Gunning Fog Index
Fog = 0.4 x (words/sentences + 100 x complex words/words)
Fog = 0.4 x (words/sentences + 100 x complex words/words) The Fog Index combines average sentence length with the share of multi-syllable words, returning a rough school grade for the passage. A score below 8 is conversational while above 12 grows demanding.
A high fog index flags prose that packs too many long words and long sentences, which drives readers away from dense documents.
This calculator takes 3 inputs: Words, Sentences, Complex words. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.