You can create a calculated field similar to the following to find the duration--depending what time part you'd like to see can be changed in the calculation:
datediff('hour', [startdatetime], [enddatetime])
Hope this helps!
I was more trying to figure out how to figure out a time duration in a specific month if the duration is covering multiple months (e.g. February 20 - April 16). I think I figured it out by using different if statements and applying the datediff equation.
Thank you for your help!
Please mark this question as "answered" in some way so others know you've found a solution. Thanks!