Hi

To display negative times you would need to switch to the 1904 Data system
ToolsCalculation1904 Date

Be aware though, that if you have any dates already entered on the sheet
under the 1900 default system, then those dates will be out by just over 4
years.
--
Regards
Roger Govier

"Sj" wrote in message
...
I am trying to work out how to calculate the difference between times for
example my sheet is to work out the finishing times of staff, so if their
set
time is 17:30 and they finish one night 17:15 and the next 17:45 i need a
formula that allows me to work out the difference but i'm getting stuck
with
the negative bit.