Calculate WOH (Work on hand)

I've been achieving the following through a series of steps - but there must be a way to do the same more efficiently. Background: Trying to chart out key potential indicators for a service org.

2 columns of dates - 1 column for 'date open' and the other for 'date closed'. I would like to count number of open in a month and number of closed in the month. The difference in any month shoud denote the work on hand remaining at end of month and be carried over to the next month.

Example: January - Open Cases = 10, Closed Cases = 6 (WOH = 4 Cases)
February - Open Cases = 5, Closed Cases = 2 (WOH = 7 Cases (Jan + Feb)

A pivot can easily give me the count for open and closed in a month - but how to easily track the WOH?

I'm sure some of you are already doing something similar and I'd appreciate some options!

Christopher

Is this what you had in mind?
//Ola