Table 1.

Five Formulae Used in the Calculation of Reading Difficulty and Grade Level, Adapted From the WebFX Tool.³¹

Grade Level Indicators
Flesch-Kincaid Grade Level	=$0.39\left(\frac{words}{sentences}\right)+11.8\hspace{0.17em}\left(\frac{syllables}{words}\right)-15.9$
Gunning Fog score	$=0.4\hspace{0.17em}\left[\left(\frac{words}{sentences}\right)+100\left(\frac{complexWords}{words}\right)\right]$
SMOG Index	=$1.0430\surd \left(30\left(\frac{complexWords}{sentences}\right)\right)+3.1291$
Coleman-Liau Index	=$5.89\hspace{0.17em}\left(\frac{characters}{words}\right)-0.3\left(\frac{sentences}{words}\right)-15.8$
Automated Readability Index	$=4.71\left(\frac{characters}{words}\right)+0.5\left(\frac{words}{sentences}\right)-21.43$