Islamic calendar

The Islamic calendar, sometimes called the 'Hijri calendar', is a calendar used by Muslims all over the world to keep track of the dates of religious and other important events. It is different from the Gregorian calendar, which is what most people in the world use today, because it is a lunar calendar, meaning it follows the phases of the moon. This means that a year is shorter than a Gregorian year, and the months don't always fall in the same season. The start of each month depends on when the first crescent of a new moon is seen. Since it is a lunar calendar, it is usually 11 or 12 days shorter than a regular year, depending on when the moon is seen.