Understanding the Islamic Hijri Calendar
The Islamic Hijri Calendar is a lunar calendar consisting of 12 months in a year of 354 or 355 days. It is used by Muslims worldwide to determine the proper days of Islamic holidays and rituals, such as the annual fasting month of Ramadan and the proper time for the Hajj (pilgrimage to Mecca).
How Does the Hijri Calendar Work?
Unlike the Gregorian calendar, which is solar-based (tracking the Earth's revolution around the sun), the Hijri calendar is strictly lunar. A new month officially begins with the sighting of the new crescent moon (Hilal). Because a lunar year is roughly 11 days shorter than a solar year, Islamic holidays "drift" backward through the Gregorian seasons over a 33-year cycle.
History of the Hijri Epoch (AH)
The epoch (starting year) of the Islamic calendar is the year 622 CE. This marks the Hijrah—the migration of the Islamic Prophet Muhammad and his followers from Mecca to Medina to escape persecution. Therefore, dates are often denoted with "AH" (Anno Hegirae), which translates to "in the year of the Hijrah."
The 12 Islamic Months
The Hijri year consists of four sacred months (Rajab, Dhu al-Qa'dah, Dhu al-Hijjah, and Muharram). The months are sequence as follows:
- Muharram (Sacred Month)
- Safar
- Rabi' al-Awwal
- Rabi' al-Thani
- Jumada al-Awwal
- Jumada al-Thani
- Rajab (Sacred Month)
- Sha'ban
- Ramadan (Month of Fasting)
- Shawwal
- Dhu al-Qa'dah (Sacred Month)
- Dhu al-Hijjah (Sacred Month - Month of Hajj)
How Our Converter Works
Our Gregorian to Hijri Date Converter tool uses the highly reliable Aladhan API to programmatically calculate the phase of the moon for any historical or future Gregorian date. While mathematical conversions are incredibly accurate for historical tracking and future planning, physical moon sightings dictate the exact commencement of significant months like Ramadan and Shawwal (Eid al-Fitr) in many Islamic communities.