Readability Level

1. The Flesch Reading Ease formula will output a number from 0 to 100 - a higher score indicates easier reading. An average document has a Flesch Reading Ease score between 6 - 70. As a rule of thumb, scores of 90-100 can be understood by an average 5th grader. 8th and 9th grade students can understand documents with a score of 60-70; and college graduates can understand documents with a score of 0-30. We calculate The Flesch Reading Ease formula as follows: 206.835 – (1.015 x ASL) – (84.6 x ASW) where: ASL = average sentence length (the number of words divided by the number of sentences) ASW = average number of syllables per word (the number of syllables divided by the number of words).

2. The Fog Scale is similar to the Flesch scale in that it compares syllables and sentence lengths. A Fog score of 5 is readable, 10 is hard, 15 is difficult, and 20 is very difficult. Based on its name, 'Foggy' words are words that contain 3 or more syllables. We calculate The Fog score by taking the percent of 'foggy' words multiplied by 100 added to the sentence length. We muliply the result by .4.

3. The Flesch-Kincaid Grade Level outputs a U.S. school grade level; this indicates the average student in that grade level can read the text. For example, a score of 7.4 indicates that the text is understood by an average student in 7th grade. We calculate The Flesch-Kincaid Grade Level by taking the average sentence length in words and multiplying it by .39. We then take the average number of syllables per word and multiply it by 11.8. We subtract 15.59 from the total of these scores.