What is the Hijri Calendar?
The Hijri calendar is the official calendar of the Islamic world. It was established by the second Caliph, Umar ibn Al-Khattab (RA), in 638 CE. The epoch (starting point) of the calendar was set to the Hijrah — the migration of Prophet Muhammad ﷺ from Makkah to Madinah in 622 CE.
Why is the Date Sometimes Off by a Day?
The Islamic day begins at sunset (Maghrib), not at midnight. Furthermore, the start of a new Hijri month is based on the actual visual sighting of the crescent moon. Because moon sighting depends on geographical location and weather conditions, computational converters can sometimes be off by +/- 1 day compared to the official local declaration of your country.