Difference between dates
Between the dates—
That is—
Weeks—
Weekdays (Mon-Fri)—
The start day is not counted, the end day is: between January 1 and January 2 there is 1 day. Weekdays are counted without public holidays.
Date plus or minus N days
Result—
How it counts
The difference is the number of calendar days from
the start date to the end date, not counting the start day (essentially
end - start). If you need it "inclusive", as for a holiday or a
rental, add 1 to the result. The years-and-months breakdown is calendar-based:
from January 15 to March 15 is exactly 2 months, even though the months have
different lengths.
Weekdays
Monday through Friday are counted, without public holidays or working-day shifts - for an exact business calendar check the official calendar for the year.