I am creating a report to reflect turnaround times:

the data is in the following format:

A B
C
1 3/14/2008 8:55:00 AM 3/18/2008 12:55:00 PM calculation

to calc the difference I have been just using B1-A1 and using general format
to get into days (this is repeated for many more columns to build a time line
so to speak)

the problem I am running into is not all the fields have values in them...

so when I run the formula I get a negative number that messes up averages
etc...

any recommendations?