I am trying to calculate the working time in the format [hh]:mm for assigned
tasks so that i will be able to log the rate at which different tasks can be
completed and help schedlue for the future.

I was planning to use a macro to copy and paste the value from a cell
containing the value =NOW() to create the start and end time. which is easy
enough. my problem lies with getting the number of worked hours based on
working pattern of 9-5 monday to friday out of the start and finish time.