"Rachel Koch" wrote:
I'm trying to get excel 2000 to return one formula if
something is true and another if it's false. This is
what I have so far: =IF(C4C3,=(C4-C3),=(C3-C4))
but it's telling me there's an error in my formula.

Because of the "=" in the middle. What you want is:

=if(c4c3, c4-c3, c3-c4)

Alternatively:

=abs(c4-c3)

But I am not sure that really meets your needs ....

C3 and C4 are times and I need to know the difference
between them.

If c4 is the later time and c4 < c3 arises because you have
gone past midnight, simply doing c3 - c4 does not give you
the correct amount of elapsed time. What you might really
want is:

=if(c4c3, c4-c3, 1 + c4-c3)

Or simply:

=c4-c3 + (c4<c3)

On the other hand, that would not detect the situation
when you have gone past midnight __and__ past c3
the following day.