leave

there is a confusion regarding counting the no. of days. will we also count sundays in calculating the no. of days of leave.suppose i take leave of say 3 months, then the no. of days will be 90 (30 days*3 months) but if i exclude sunday from this the no. of days come to 78 (90 days - 4 sunday*3 months).

this saves a considerable time of extended training(if any).
wats ur experience or opinion guys?