FOGIndex

Under.zip (XInfo) "FOGIndex" - If the length of the selection is under 100 characters, returns the FOG index of the entire document, otherwise the FOG index of the selected text.

The Fog Index of Readability I calculate as 0.4 * ( (words/sentences) + (100 * (long words/words))), that is, 0.4 times the average number of words per sentence plus 100 times the number of long words divided by the number of words.