How the gap is counted
- Days: the difference between the dates, not counting the first day. From the 1st to the 10th of a month is 9 days. To count both days, add one.
- Months: whole months from the same day number, with the rest in days. For Hijri dates the months follow the Umm al-Qura calendar.
- The number of days is the same whether you enter the dates in Hijri or Gregorian, because a day is the same day in both.
An Umm al-Qura month has 29 or 30 days, so the calculator reads each month's length from the official calendar instead of estimating.
