Calculating number of days between dates excluding week ends.

Hi,

I have to calculate no. of working days taken to complete a task, excluding weekends (Fri. & Sat).
I am having start date and end dates, data range from 2014 to 2016.

Example:
Work allotted on : 13th November 2014
Work completed on : 26th November 2015.

I need to know howmany working days taken to complete the task, excluding week ends (Friday & Saturday).

Can anyone help with a formulae to solve.

Thanks,
G. Roger

Awesome!! Thank you Ben Van Johnson