I enter hundreds of start and stop times to determine room occupancy time. I
would like to get away from inserting the colon in the time, which would
greatly enhance entries with the number key pad. How do I format a cell to
allow entry of a 4 digit time (e.g. 1955 or 2315) in military/international
format? I need to subtract Start from Stop Time, but the answer can be in
hh:mm format.

Thank You in advance for any helpful suggestions.