Hi Chi, surely the first line of your example should return 24:00?

if it is over 23:59 excel will start at 00:00 again, try changing the format
of your cells to [hh]:mm

Hth
Stu

"Chi" wrote:

Hi,

I would like to calculate the hours between two columns: First Contact (G)
and Appointment (H) with (m/d/yyyy) h:m AM/PM) format.

First Contact (G) Appointment (H) (J) (= H-G)
1/2/2010 10:00 AM 1/3/2010 10:00 AM 0:00
1/1/2010 8:00 AM 1/1/2010 9:00 AM 1:00
1/1/2010 8:15 AM 1/1/2010 8:30 AM 0:15

I added the formula (=H-G) on column J to calculate the difference between
(H) and (G) However, I don't understand why (1/2/2010 10:00 AM) (1/3/2010
10:00 AM)=0:00. It should be 12 hours.( the first line of my example). The
last two lines are correct, but the first line is wrong. Please help.
Thanks
Chi

On the column