Please convert Work Date as Start & End Date.
Then use - NetWorkDays([Start Date],[End Date])
if you want you can specify holidays as well. Please check the below example.
need to specify the holidays in networkday().
For example you want networkdays between 2006-12-18 and 2006-12-31.
If you just give this without the specific holidays you will get 10 as output.
But say you have holiday on 2006-12-25 and 2006-12-26
Then specify like this
networkdays ('2006-12-18', '2006-12-31', '2006-12-25', '2006-12-26')
and you will get answer as 8.