One way:

For negative hours, check the 1904 Date system checkbox in
Tools/Options/Calculation (note: if you have dates in the worksheet,
they will be advanced by 4 years and 1 day. This is a one-time event,
all subsequent dates you enter will be handled correctly).

For hours 24, Format/Cells/Number/Custom [hh]:mm


In article ,
"Peterlg" wrote:

I am using Excel to calculate the hours I have worked, and compare with the
standard working hours. Can someone help me to:

a)Show hours of more than 24 as hh:mm rather than dd:hh:mm

b)Show negative time where I have worked less than the standard hours.

Thanks,

Peter