Fog Index
From Simple English Wikipedia, the free encyclopedia
The Fog Index is one measure of textual difficulty.
To calculate the Fog Index of a passage, do the following:
- Count the number of words in the paragraph, W.
- Count the number of sentences in the paragraph, S.
- Count the number of hard words of three syllables or more, HW.
- Apply the following formula: (W/S + HW/Wx100)x0.4
The Fog Index gives the number of years of education that a reader needs to understand the paragraph. Typically, in technical documentation, aim for a Fog Index between 10 and 15. The Fog Index formula implies that short sentences written in plain English achieve a better score than long sentences written in complicated language.
