Format of a cell is immaterial to its calculation. Formatting controls only
the display, not the way it's stored internally. Any formula that works with
time, will work with all formats of it.

In your response, you should indicate that you are converting time to
decimal hours. The result would need to be formatted as a number.


Regards,
Fred.
"Sum Ting Wong" <SumTingWong@thebarattheendoftheVenusianLightnigBo lt.org
wrote in message ...




=IF((OR(H10="",G10="")),0,IF((H10<G10),((H10-G10)*24)+24,(H10-G10)*24))

G10 is start time, H10 is stop time. Change to your start and stop
cell names.

Sorry, but 24 hour format is required here. There may be a 12 hr
format version I do not know about.