Microsoft Word's Spelling and Grammar feature not only checks the structure of your document; it also measures its readability. Word uses two tests to determine this. The Flesch Reading Ease score is calculated from "206.835  (1.015 x ASL)  (84.6 x ASW)." The FleschKincaid Grade Level is obtained from "(.39 x ASL) + (11.8 x ASW)  15.59." In both formulas, average number of syllables per word or ASW is computed by dividing the number of syllables by the total number of words. With this information, you can use basic algebra to get the syllable count of your document.
Things You'll Need
 Calculator (optional)
Checking Readability Statistics

Launch Microsoft Word, and open your document.

Make sure that readability statistics is enabled. To do this, click the Microsoft Office button and then click on "Word Options." Click "Proofing" in the Category pane, and make sure that both "Check grammar with spelling" and "Show readability statistics" are checked. Click "Ok" to save your changes.

Press "F7" to start the "Spelling and Grammar" tool. You may also do this by going to the "Review" tab on your ribbon toolbar and then clicking on "Spelling and Grammar." If you are running MS Word 2003 or earlier, open the "Tools" menu and then choose "Spelling & Grammar."

Follow the "Spelling & Grammar" tool. Make necessary corrections as you go. After checking your document, Word displays the "Readability Statistics" window. Take note of the values for "Words," "Sentences," "Flesch Reading Ease" and "FleschKincaid Grade Level."
Using Flesch Reading Ease Score

Divide the total number of words by the number of sentences. This gives you the average sentence length or ASL.

Multiply the average sentence length by 1.015, and add the product to the Flesh Reading Ease score. Subtract the result from 206.835.

Divide the difference by 84.6. This gives you the ASW.

Multiply the ASW by the total number of words.

Round off the result to the nearest whole number. This is the total number of syllables in your document.
Using FleschKincaid Grade Level

Divide the total number of words by the number of sentences. This gives you the average sentence length or ASL.

Multiply the ASL by 0.39. Subtract this from the FleschKincaid Grade Level. Add 15.59 to the result.

Divide the sum by 11.8. This gives you the average number of syllables per word or ASW.

Multiply the ASW by the total number of words.

Round the result to the nearest whole number. This is the total number of syllables in your document.
Tips & Warnings
 Instead of performing calculations manually, use Microsoft Excel to compute for the total number of syllables in your document. Assuming that cells "A1," "A2" and "A3" contain the values for "Words," "Sentences" and "Flesch Reading Ease," you can obtain the total number of syllables by entering the formula "=A1*((206.835A31.015*(A1/A2))/84.8)" into a blank cell.
References
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