Understand readability scores
Each readability test bases its rating on the average number of syllables per word and words per sentence. The following sections explain how each test scores your file's readability.
Flesch Reading Ease test
This test rates text on a 100-point scale. The higher the score, the easier it is to understand the document. For most standard files, you want the score to be between 60 and 70.
The formula for the Flesch Reading Ease score is:
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)
Flesch-Kincaid Grade Level test
This test rates text on a U.S. school grade level. For example, a score of 8.0 means that an eighth grader can understand the document. For most documents, aim for a score of approximately 7.0 to 8.0.
The formula for the Flesch-Kincaid Grade Level score is:
(.39 x ASL) + (11.8 x ASW) – 15.59
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)
Understand how languages affect readability scores
The languages that you use in a document can affect how your Office program checks and presents readability scores.
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If you set up Word to check the spelling and grammar of text in other languages, and a document contains text in multiple languages, Word displays readability statistics for text in the last language that was checked. For example, if a document contains three paragraphs — the first in English, the second in French, and the third in English — Word displays readability statistics for the English text only.
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For some European languages within an English document, Word displays only information about counts and averages, not readability.
