Excel will calculate negative times, it just won't display them. So your
formulas will work regardless. I expect that your problem is you need to
check for start times after 7am, and end times before 6pm. Something like:

b3 =max(0,$a$1-b1)
b4 =max(0,b2-$a$2)

Remember to format these results as Time.

Regards,
Fred

"rh33a" wrote in message
...
Dear Friends,

I'm stuck with this formula.. can you please help me?

here is the worksheet:

A1 = 7:00
A2 = 18:00

B1 = IN
B2 = OUT
B3 = MORNING OVER TIME
B4 = AFTERNOON OVERTIME
B5 = TOTAL OVERTIME

what I've done:

B3 = $A$1-B1
B4 = $A$2-B2
B5 = B3+B4

However, for the B3 formula, it keeps showing "######" as the result (for
negative result), therefore, I cannot find the total overtime correctly.

can you help me please?

thank you in advanced.

Rh33a