Use conditional formatting.

A2 = 13:15
B2 = 13:18

C2 = formula:

=ABS(A2-B2)

C2 conditional formatting:
Formula Is: =(A2-B2)*24<0
Set the font color to red
OK out

Biff

"Six Sigma Blackbelt" wrote in
message ...
I have a worksheet that displays appt. time & actual time in, some of my
actual time in data is greater than the appt. time ex: 13:15 appt time,
Actual time in 13:18, the cell should show :03 in red? but instead it
gives
me a #VALUE!. How can I display this time, and show it as a negative time.