Excel can calculate, but not display, negative times. You can
enable it to display negative times, by switching to the 1904
Date System. Go to the Tools menu, choose Options, then the
Calculation tab. There, check the 1904 Date System option. Note,
however, that this will cause existing dates in the workbook to
be 4 years off.


--
Cordially,
Chip Pearson
Microsoft MVP - Excel
Pearson Software Consulting, LLC
www.cpearson.com


"Xavier" wrote in message
...
hello.

i have a xls with 3 rows with the cell fprmat as time hh:mm

example of the values
col 1 - nr of hh:mm worked on a day
col 2 - nr of standard hh:mm to work on a day
col 3 - calcualated - col1 -col2 - it shows if someone has
worked more or
less then the default time

example

08:00 08:00 00:00 ok
09:30 08:00 01:30 ok
07:00 08:00 Problem !!!! - i want here to have -01:00

is this possible?
thanks