Thanks, for the discussion, very interesting. I'm not sure that the
code above solves my problem though. How can I count each occurance
of task A in the timeslot 06:00 to 06:10 for 200 rows of data, only if
the duty occurs on a Monday and then place the result in a summary
sheet, then move onto the next time slot, and after all timeslots have
been queried, query the same data for Task B, after that, I need to do
it all again but ask if Tuesday is a day on which the duty occurs etc
etc. Each row represents a duty and its content (tasks split to
minute blocks of time), the row also details the days on which the
duty occurs.

Like I say a COUNTIF works, but when I used this I have seven
worksheets (one for each day of the week), now I only have the one
worksheet and state for each duty the days the duty occurs.

fingers are crossed,
kind regards,
Matt