How long between two dates?
Two dates, and the span between them in both calendars' own units — or one date and a duration, and the day it lands on. People use this for visa windows, contract periods and notice deadlines: spans that have to be reckoned across two calendars at once.
The answer
Enter two dates, or a date and a duration.
Save this date to your calendarThe count is of elapsed days, not of days touched: from a date to itself is 0 days, and to the day after it is 1.
Months and years are counted in the calendar you entered the date in, because a month is not the same length in both. Days and weeks are the same either way.
Why there is no working-day count
A working-day number that ignores public holidays is a wrong number, and Iran's public holidays follow the lunar calendar, whose dates this site will not guess. For the shape of the two working weeks, the Tehran time compass shows both at once.