Counting total hours worked within m

(Title was supposed to say: Counting total hours worked within multiple days)

Is there anyway to calculate the # of work hours spent on a project given 2
seperate dates and times, taking into account a work day of 8-5 with an hour lunch?

For example, if I work 8-5, start a project on 8/3 at 9 and finished it on
8/7 at 4, the answer would be 22 work hours. Ideally, i'm trying to avoid having a lunch out/lunch in column or having to enter each day into a spreadsheet...

I'm thinking a datediff equation

Any ideas would be greatly greatly greatly appreciated.

Thanks!