substracting hours and minutes

[beginner]

hi.
i've been working on a formula that lets me know the time
it takes to response to the customer.
i'm considering 1 hour for lunch: from 1 pm to 2 pm.

=IF(AND(A5>1300,A5<1400),B5-1400+(B5<A5)-1,B5-A5+(B5<A5))

that formula doesn't mind about the lunch time.
could you give me hand?
tia.

 

[Frank Kabel]

Hi
first: store your times as real Excel time values (e.g.
09:00) This makes the formulas easier.

So if A5 stores your starting time and B5 the ending time
(and both can not span midnight) try

 

[Dave R.]

It looks like it does 'mind' the lunch time. If the call came in between
1301 and 1359, it subtracts 1401 from the end-call time. This looks like
you're saying if the call came in during lunch time, you want to calculate
based on when people are actually there to do the support? What's the
problem with what it's doing now?