It is an extremely complex process. See:
http://gregmaxey.com/word_tip_pages/...cy_report.html
You might be able to user this:
Code:
Sub ScratchMacro()
'A basic Word macro coded by Greg Maxey
If ActiveDocument.ComputeStatistics(wdStatisticWords) > 3000 Then
MsgBox ActiveDocument.ComputeStatistics(wdStatisticWords) - 430
End If
End Sub