The term "11 september 2025 hijriah tanggal berapa" is an Indonesian interrogative phrase. Grammatically, it functions as a question seeking the corresponding date in the Hijri calendar for a given Gregorian date. Based on standard astronomical calculations, the Gregorian date of September 11, 2025, corresponds to the Hijri date of 18 Rabi'ul-Awwal 1447 AH.
The conversion between the Gregorian and Hijri calendars requires understanding their fundamental differences. The Gregorian calendar is a solar calendar with 365 or 366 days, while the Hijri calendar is a purely lunar calendar with 354 or 355 days. This discrepancy causes Hijri dates to shift backward by approximately 11 days each year relative to the Gregorian calendar. The start of a new Hijri month is determined by the sighting of the new crescent moon. While computational methods, such as the Umm al-Qura calendar, provide a highly accurate prediction for administrative purposes, the traditional method of physical moon sighting ( ru'yatul hilal) can result in a one-day variation of the start of the month depending on geographical location and atmospheric conditions.
Consequently, the calculated date of 18 Rabi'ul-Awwal 1447 AH should be considered a precise astronomical forecast. For practical applications, particularly for scheduling religious observances such as fasting or festivals, the definitive date in a specific community is subject to confirmation by local religious authorities or moon-sighting committees. Therefore, while the calculation provides the most likely date, final verification from a local authority is recommended for official or religious purposes.
