Try 1904 type date format:

Tools/Options/Calculation tab/(bottom left corner)

Note that changing to the 1904 date system will cause all your
existing dates to be off by 4 years and a day

OR

F1: <end time
F2: <start time


As Excel shows negative times as ##### take largest from smallest and prefix
by negative sign.

=IF(F1<F2,TEXT(F2-F1,"-" & "hh:mm"),F1-F2)



"Jelinek" wrote:

i have two columns of data both time formats when i subtract one from the
other it displays ###### if it is a minus value is there away to get round
this i would like to view the diffrence even if it is a minus amount.

Thanks

Simon