The Islamic (Hijri) calendar is a lunar calendar used by Muslims worldwide to determine the dates of religious observances and holidays such as Ramadan, Eid al-Fitr, Eid al-Adha, and Hajj.
The Islamic calendar consists of 12 lunar months and is approximately 11 days shorter than the solar year. It was established in 622 CE, the year of the Prophet Muhammad’s migration (Hijrah) from Mecca to Medina, marking the beginning of the Islamic era.
The Islamic (Hijri) calendar includes several important religious observances. Dates vary each year based on lunar sightings, but these are among the most significant:
- Islamic New Year (1 Muharram) – Marks the beginning of the new Hijri year.
- Day of Ashura (10 Muharram) – A day of reflection and fasting; observed differently by Sunni and Shia Muslims.
- Ramadan – The ninth month of fasting from dawn to sunset, commemorating the first revelation of the Qur’an.
- Laylat al-Qadr – The “Night of Power” during Ramadan, believed to be when the Qur’an was first revealed.
- Eid al-Fitr (1 Shawwal) – Festival of breaking the fast, celebrated at the end of Ramadan.
- Hajj (8–13 Dhu al-Hijjah) – The annual pilgrimage to Mecca, required once in a lifetime for those who are able.
- Day of Arafah (9 Dhu al-Hijjah) – The most important day of Hajj and a recommended fast for those not on pilgrimage.
- Eid al-Adha (10 Dhu al-Hijjah) – Festival of sacrifice, commemorating Prophet Ibrahim’s devotion and willingness to sacrifice his son.
- Mawlid al-Nabi (12 Rabi‘ al-Awwal) – Celebration of the birth of the Prophet Muhammad (peace be upon him).
- Isra and Mi’raj (27 Rajab) – Commemorates the miraculous night journey and ascension of the Prophet Muhammad.
Islamic holidays begin with the sighting of the new moon. Since each lunar month is 29 or 30 days long, dates vary by location and astronomical observation. This lunar-based system causes holidays to shift about 11 days earlier each year on the Gregorian calendar.
The Islamic calendar connects Muslims to their faith and heritage. It guides acts of worship, charity, fasting, and pilgrimage—serving as a spiritual rhythm throughout the year.
Major holidays include Ramadan, Eid al-Fitr, Eid al-Adha, and the Hajj pilgrimage, along with observances such as the Islamic New Year and Mawlid al-Nabi.
Because the Islamic calendar is lunar, it is about 11 days shorter than the solar Gregorian year. As a result, holidays move earlier each year on the Gregorian calendar.
The months and structure are the same globally, but exact holiday dates can differ slightly by country due to local moon sighting practices.