Calculate hours and rate to equal charge

Question

Ok so i am trying to figure a couple of things out on sharepoint o365, So the fields we are working on are Start time, Finish Time, Total Time, Rate, Billable. So currently we work out our total time based on =TEXT([Finish Time]-[Start Time],"h:mm") which works for us. i thought it would just as simple to add a Rate and billable fields, Billable= Total Time * Rate buts its giving me a different number eg: (Start)15/02/2017 9:30 PM (Finish)16/02/2017 7:30 AM (total)10.00*(rate)$40.00 = (billable)$16.67

Answer 1

Sorted it out, using this formula =HOUR([Column2]-[Column1]) Ref: https://msdn.microsoft.com/en-au/library/bb862071(v=office.12).aspx