The Islamic calendar is a lunar-based system that has deep religious and cultural significance for Muslims. While the Gregorian calendar follows the solar year, the Islamic calendar is based on the moon’s cycles. Each month in the lunar calendar lasts 29 or 30 days. Thus, a lunar year is made of 354 or 355 days (approximately 11 days shorter than the solar year).
Like any other religious community, the calendar followed by Muslims keeps a tab on key religious events and festivals such as Ramadan, Eid al-Fitr, Eid al-Adha, and the Hajj pilgrimage. Most Muslim-majority nations use the Gregorian calendar for civil purposes and the Hijri calendar for religious purposes.
Historical Background of the Hijri Calendar
The term “Hijri” is derived from the Arabic word hijra, meaning “migration”. This refers to Prophet Muhammad’s ﷺ journey from Makkah to Madinah in 622 CE. The Hijra was a turning point in Islamic history. It marked the establishment of the first Muslim community (ummah) under divine guidance. The Hijri calendar was formally adopted during the caliphate of Umar ibn al-Khattab in 638 CE. The companions of Prophet Muhammad ﷺ consulted on a suitable starting point for the Islamic era. After considering many key events such as the Prophet’s birth and the first Quranic revelation, they finally chose the Hijra, as it symbolised the dawn of the Islamic state.
How the Lunar Calendar Works
The Islamic calendar operates on a purely lunar system, with each month beginning upon the sighting of the new crescent moon. A lunar cycle lasts approximately 29.5 days, resulting in months of 29 or 30 days. Unlike solar calendars, which align with seasonal changes, the lunar year is about 11 days shorter, causing Islamic months to shift earlier each Gregorian year.
Traditionally, Muslim communities relied on visual moon sightings to declare the start of a new month. If the crescent was seen on the 29th night, the new month began the next day; otherwise, the current month extended to 30 days. Today, advancements in astronomy allow for precise lunar calculations, reducing reliance on physical sightings. However, some scholars and communities still prefer the traditional method, arguing that it preserves the Prophet’s Sunnah. Others combine both approaches, using calculations to predict dates while requiring official moon sightings for confirmation. Because the lunar cycle is shorter than the solar cycle, Islamic months do not align with seasons. For example, Ramadan moves through all seasons over a 33-year cycle, ensuring Muslims experience fasting in varying conditions – long summer days and short winter ones and vice versa. This gives a dynamic and balanced experience of worship over time.
12Months of Islamic Calendar
The Islamic lunar calendar comprises 12 months, each imbued with unique historical and spiritual significance. They are Muharram, Safar, Rabi al-Awwal, Rabi al-Thani, Jumada al-Awwal, Jumada al-Thani, Rajab, Sha’ban, Ramadan, Shawwal, DhulQa’dah and DhulHijjah. Four of these months, Muharram, Rajab, DhulQa’dah, and DhulHijjah hold special sacred status as ordained in the Quran: “Indeed, the number of months with Allah is twelve [lunar] months in the register of Allah, of which four are sacred” (9:36). During these sacred months, warfare was traditionally prohibited except in cases of self-defence, creating periods of peace that facilitated safe pilgrimage and spiritual reflection.
The calendar begins with Muharram, which marks the Islamic New Year and includes the significant Day of Ashura on the 10th, commemorating both Prophet Musa’s miraculous deliverance and the martyrdom of Imam Hussain. Rajab, the 7th month and first of the sacred months, prepares believers for Ramadan and includes the miraculous Night Journey of the Prophet.
Ramadan stands as the pinnacle of Islamic worship, a month of fasting, Quranic revelation, and intensified devotion. DhulQa’dah, another sacred month, traditionally ensured safe travel for pilgrims approaching Hajj season. The final month, DhulHijjah, contains the Hajj pilgrimage and Eid al-Adha, with its first 10 days being among the holiest of the year – particularly the Day of Arafah when sins are forgiven.
The Moon in Islamic Teachings
The Quran mandates moon-based timekeeping: “They ask you about the crescent moons. Say, ‘They are measurements of time for the people and for Hajj.’” (Quran 2:189).
Tafhim-ul-Quran explains the verse thus: “The phases of the moon have attracted the attention of mankind in every age, and different kinds of rites and superstitions have been connected with these in every country. The Arabs also had some superstitions connected with these. They took omens from them for journeys, marriage ceremonies, business, etc., and performed some superstitious practices, for they believed that the phases and the eclipse of the moon affected their fortunes. Therefore, they questioned the Holy Prophet concerning this. Allah answered their question and informed them that the phases of the moon were nothing but natural calendar in the sky to indicate dates of the month to the people simultaneously throughout the world. Hajj has been specially mentioned in this connection because of its religious, cultural and economic importance to the Arabs. Four months of the year were fixed for Hajj and Umrah during which war was suspended and the routes were made safe, and business flourished on account of peace.”
The crescent moon is a prominent symbol of Islam and Muslim rule and can be found in Muslim architecture, flags, and other insignia. It represents guidance, beauty, and spirituality in poetry and art. Muslims have never worshipped the moon as Islam forbids revering celestial bodies, stressing monotheism. It is noteworthy that modern science affirms the moon’s role in tides, biological rhythms, and astronomy.
Usage of the Hijri Calendar Today
Some Muslim-majority nations like Egypt and Indonesia use the Gregorian calendar for civil affairs. Others like Saudi Arabia and GCC states officially adopt the Hijri calendar for religious and administrative purposes. Many Muslims worldwide reference both systems, using the Gregorian for daily life and the Hijri for Ramadan, Eid, and Islamic events. Digital apps now facilitate easy conversion between the Hijri and Gregorian calendar. It is a matter of satisfaction that Muslims continue to honour the sacred months, moon sightings, and Quranic teachings. Even with the advances in technology, the Hijri calendar serves as a chain tied to Islam’s heritage. It invites the Muslims to reflect on Allah’s signs in the cosmos.