Need to calculate start date

[Novice86]

I have a table to track machine hours needed and the date and hour an order is due. I'd like excel to return required start date and time in a cell. My workweek starts at 12am on Sunday and ends at 8pm on Friday. Due date is in column E, runtime hours in column f, I need required start date in column H. Example would be (column e) order due 3/21/16 7am, (column f) runtime 52 hours.

 

[RCBricker]

if you format column F so the data is entered in hh:mm:ss then all you need is a sum in column H

so (as per your example)

column e is 38/21/2016 7:00
column f is 52:00:00

then

column H is =E3+F3

and it returns 03/23/2016 11:00

 

[Novice86]

I need to subtract working day hours only. This sum function would include Saturday, Sunday, and hours we are not working on Friday night?

 

[RCBricker]

always round hours for runtime? no minutes or seconds correct?

 

[Novice86]

Correct.

 

[RCBricker]

I need to subtract working day hours only. This sum function would include Saturday, Sunday, and hours we are not working on Friday night?

try this out

=IF(OR(WEEKDAY(E2-SUM(F2/24),2)=7,WEEKDAY(E2-SUM(F2/24),2)=6),E2-
SUM(SUM(SUM(F2-HOUR(E2))+52)/24),
SUM(E2-SUM(F2/24)))