On the Tools menu, click Options, and then click the Spelling & Grammar tab.
Select the Check grammar with spelling check box.

Select the Show readability statistics check box, and then click OK.

On the Standard toolbar (toolbar: A bar with buttons and options that you use to carry out commands. To display a toolbar, press ALT and then SHIFT+F10.), click Spelling and Grammar .

When Microsoft Word finishes checking spelling and grammar, it displays information about the reading level of the document.

Notes

If you've 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 third English paragraph only.

For some European languages within an English document, Word displays only information about counts and averages, not readability.

SOURCE: http://office.microsoft.com/en-us/wo...896011033.aspx