Tony,

Before I begin to craft a formula for your query, please explain to me how you arrive at 8 and 19 for J7 and J8 respectively?

Hi Jeffrey
J8:
For the task on Sheet1!Row 5 the number of working days between 1 June 16 and the task end date is "3".
Then I add the number of working days between 1 June and the task end date for Sheet 1!Row 6 which is "16".
This makes a total of 19 days for Business Support for June.
J7:
For the task on Sheet1!Row 7 the number of working days between 1 June and the task end date is "8".
This makes a total of 8 working days in June.
Hope this helps.
Thanks Jeffrey.
Tony