I asked this question yesterday,
My spread sheet is used to track arrival times at a specific location. The
location has a scheduled arrival time in column C, in column D I enter the
actual arrival time when a vehicle arrives, and column E calculates the
difference.

I use the 1904 time system so Ill be able to calculate and show negative
time. Column E is set with =IF(D3=€�€�,€�€�,D3-C3) this will have column E appear
blank until the actual time is entered.

Without =IF(D3=€�€�,€�€�,D3-C3)in column E and with =D3-C3 this will show the
negative of the scheduled time i.e. -4:59 or -18:44. The schedule time is
always present in column C.

The trouble Im having now is; often a vehicle will arrive right on time
which will calculate like 0:00.
This is good, but after a few on time calculations some of will appear like
this -0:00, and thats not good.

Would anyone know of a way to prevent the negative sign from appearing when
the arrival time is on time?

Pete_UK answered;
If you changed it to this:
=IF(D3=€�€�,€�€�,CEILING(D3-C3,1/24/60))
this will round your result up to the nearest minute, so this should
correct for -0:00.

Today I tried that, and it worked for the result of 0:00. But when the
result is a minus number less than 0:00 the formula will show #NUM. If
possible I need to have the actual negative number.
Any help is appreciated.