The Hijri Calendar Explained: How It Differs from the Gregorian Calendar
The Hijri calendar is a lunar calendar used by Muslims around the world. Year 1 AH marks the Hijra, the migration of the Prophet Muhammad from Makkah to Madinah in 622 CE.
How it works
The calendar has 12 months, and each month begins with the sighting of the new moon. A month lasts 29 or 30 days, so a Hijri year has about 354 or 355 days.
Why it differs from the Gregorian year
The Gregorian calendar follows the sun and has 365 or 366 days. A Hijri year is about 10 to 11 days shorter, so Islamic dates move earlier each year. This is why Ramadan falls in different seasons over time.
The twelve months
Muharram, Safar, Rabi al-Awwal, Rabi al-Thani, Jumada al-Awwal, Jumada al-Thani, Rajab, Shaban, Ramadan, Shawwal, Dhul Qadah and Dhul Hijjah.
Why converted dates can differ
Tabular calendars use fixed calculations, while many countries rely on actual moon sighting. For this reason a converted date can differ by a day from the one announced locally. For religious observances, follow your local announcement.
When does an Islamic day begin?
Traditionally the Islamic day begins at sunset, not at midnight. This is why an Islamic date can seem to start the evening before the matching Gregorian date.
Some important dates
- 1 Muharram: the Islamic New Year.
- 10 Muharram: Ashura.
- Ramadan: the ninth month, the month of fasting.
- 1 Shawwal: Eid al-Fitr.
- 10 Dhul Hijjah: Eid al-Adha.
Where Hijri dates are used
Many Muslims use them to plan religious occasions, and Saudi Arabia also uses an official calculation-based calendar called Umm al-Qura for administrative purposes.
Frequently asked questions
Why does Ramadan start on different days in different countries?
Some countries follow local moon sighting while others follow calculations or the sighting from another region, so start dates can differ by a day.
How many days are in a Hijri year?
About 354 or 355 days, compared with 365 or 366 in the Gregorian year.
Convert dates with our Hijri Date Converter.