With your data in A1:E7, enter in B3:

=IF(B$1=$A3,0,$A3-B$1)

--
HTH

Sandy
In Perth, the ancient capital of Scotland
and the crowning place of kings


Replace @mailinator.com with @tiscali.co.uk


"Kim Shelton at PDC" wrote in
message ...
I have a chart setup to calculate the converted time between to time frames
example. The crew started at 7:00am and ended at 10:00 am. Everything
works
except with the time is started at 7:15 am and ended at 7:00 am which of
course is not possible but because it is a continuous chart I have it
setup
that way. I want the answer to be 0:00 instead of the ##### symbols error
that it gives me. See sample below. My chart continues until 10:00 pm on
the end of and out.
IN 7:00 AM 7:15 AM 7:30 AM 7:45 AM
OUT
7:00 AM 0:00 ##### ##### #####
7:15 AM 0:15 ##### ##### #####
7:30 AM 0:30 0:15 0:00 #####
7:45 AM 0:45 0:30 0:15 0:00
8:00 AM 1:00 0:45 0:30 0:15