The answer is negative 8 hours. But Excel cannot display negative times. If
this is what you actually want to do, post back, and we'll give you some
options.

If you really meant 11:15 - 3:15, it's simple subtraction:
=a2-a1
Format as a time.

Regards,
Fred

"gma" wrote in message
...
how do you calculate hours i.e.
3:45am-11:15am = ______hrs?