I have a drop down list in C5 and D5 with times ranging from 12.00 AM to
11.45 PM.

I have the following formula in E5 which works well to calculate hours
worked:-
=IF(OR(C5="",D5=""),"",IF(D5<C5,D5+1,D5)-C5)

What I would like to do is incorporate the following:-
=IF(OR(C5="",D5=""),"",IF(AND(C5=5.45 pm,D5=18.30
pm),1,IF(D5<C5,D5+1,D5)-C5))
(Obviously the above syntax is incorrect)

In other words if the time in C5 is 5.45pm AND the time in D5 is 6.30pm then
the total in E5 would be 1 hour.

C5 and D5 are formatted as h.mm AM/PM and E5 as h.mm

Any help appreciated.
Sandy