Formula to count the number of different months in a range

Originally Posted by XOR LX

Are you sure?

Yep!

What I mean is that it will count 3-Sep-2012 and 22-Sep-2012 as the same (because they are both September 2012) but it will count 4-Sep-2013 and 15-Sep-2012 as different (i.e. count twice) because the two dates are in different Septembers