It will take you just a few seconds to set up Microsoft Word to report your readability statistics.
Word does all the work. You'll have your report every time you do a spellcheck.
Readability statistics includes two valuable measures - the proportion of passive writing in your text and your score on the Flesch Reading Ease Scale.
Those scores will be more useful if you have some benchmarks.
What's your passive score?
Think of passive writing as boring and vague. 'The email was written last week' is passive. Who wrote it? Maybe we need to know.
Some big organisations set a standard of no more than 20 per cent passive - implying 80 per cent active.
Twenty per cent passive is a challenge for most writers and makes a sensible target. I'm a fanatic so I prefer one percent passive - and even then I want a good reason for not using the active voice. (Say, it's more important to emphasise what happened and who did it is irrelevant, or there's no other way to be diplomatic.)
The Flesch Reading Ease formula (invented by Rudolph Flesch) measures the average number of syllables and words in your sentences and converts them to a score. Your score will tell you about the simplicity of your sentences and the formality of your language.
Always take the role of your document into account. Even a well-written technical or academic document for readers who know the jargon and concepts will usually have a lower score than say a brochure for general readers.
Rudolf Flesch says Harvard Law Review scores in the low 30s, Time Magazine 50, Readers Digest 65 and Dr Suess's Green Eggs and Ham 93.
In technical writing you might be content with the low 40s, but for everything else, revise if you are not above 50. Could you break up some of those longer sentences? Could you use simpler, more informal words? Aim for the mid-60s.
Make it happen
For the various versions of Word you need Readability Statistics.
File/options/proofing, then tick the Readability Statistics option.
Once you've set it up, you'll see your readability statistics after every spellcheck.
Treat the figures as a rough guide and they'll be a useful addition to your writing and editing toolkit.