A lunar calendar

Islam measures its year by the moon. The Quran sets the number of months at twelve and points to the phases of the moon as a way of marking time:

"Indeed, the number of months with Allah is twelve [lunar] months."

— Quran 9:36 (Saheeh International)1

"They ask you about the new moons. Say, 'They are measurements of time for the people and for Hajj.'"

— Quran 2:189 (Saheeh International)2

"It is He who made the sun a shining light and the moon a derived light and determined for it phases — that you may know the number of years and the account [of time]."

— Quran 10:5 (Saheeh International)3

Because the lunar year is about eleven days shorter than the solar year, Islamic months — including Ramadan and the month of Hajj — move gradually through the seasons.

Counted from the Hijra (AH)

The Islamic calendar counts its years from the Hijra, the Prophet's migration to Medina in 622 CE (see The Life of the Prophet ﷺ). Dates are therefore marked AH ("after Hijra").567

The two Eids

Islam has two great festivals, both established by the Prophet ﷺ in place of older celebrations:

"Allah has given you two days better than them: the day of breaking the fast (Eid al-Fitr) and the day of sacrifice (Eid al-Adha)."

— Sunan Abi Dawud 1134 (Sahih)4

  • Eid al-Fitr ("festival of breaking the fast") comes at the end of Ramadan, celebrating the completion of the month of fasting.
  • Eid al-Adha ("festival of the sacrifice") falls during the season of the Hajj and commemorates the Prophet Abraham's willingness to sacrifice his son. It is marked by the sacrifice of an animal whose meat is shared with family and the poor.567

Both days begin with a special congregational prayer and are times of gratitude, generosity, and gathering.

In short

The Muslim year is a lunar calendar counted from the Hijra (AH), and its high points are the two Eids — one crowning the fast of Ramadan, the other the pilgrimage of Hajj — both occasions of worship, charity, and joy.