I have already had very good help, but unfortunately, none of the solutions
which can handle the needs I have to consider.

I can only make a form that works properly, either when finishing is before
24:00 or after 24:00. I can not make a form that can handle END times both
before and after 24:00.

So I have to just to try once mo)

I would be very happy if I could get help to produce a formula which is able
to calculate hours in a time when "finishing" can be both before and after
at. 24:00.

I can only make a formular, who works

For example: Start: 16:00, End: 6:00 total hours = 14 ,
and hours of these between 18:00 to 22:00 = 4

and another example: Start: 16:00, End: 21:00 total hours = 6,
and hours of these between 18:00 to 22:00 = 3

It is the counting of the time between 18:00 and 22:00 there is a problem,
totaltid is not necessary to count.

Sincerely,
H. Nissen