adding time

[Guest]

I am just learning how to add time but I need to add time from pm to am.
When I do the basic formula, it obviously gives me a negative number. Is
there a different formula so i can have a positive answer. Please help. I
am using Microsoft Excel 2003

 

[David Biddulph]

If you are ADDING, then it won't give a negative number. If you are
SUBTRACTING, then you may need to change =B1-A1 to either
=MOD(B1-A1,1) or
=(B1-A1)+(B1<A1)

 

[Peo Sjoblom]

What is the basic formula?

If I add time I never get a negative result, only if I subtract

If you meant that you subtract end_time minus start_time then you can use

=End-Start+(End<Start)

or

=MOD(End-Start,1)