Calendar
The Islamic lunar calendar
The Islamic calendar is lunar (Hijri). A month begins with the sighting of the young crescent — the hilal; it sets the start of the fast, the feasts and the days of Hajj.
The thin crescent of the young moon. Its appearance begins a new month, in particular Ramadan.
History
How it began
A journey
A year led by the Moon
Scroll — the Moon will change phases, the dial will show where you are in the year, and the story will take you from the first crescent to the great festivals.
A month begins
Hilal — the birth of a month
A new month begins not with a number in a table but with the sky: when, after sunset, a thin crescent — the hilal — becomes visible. "They ask you about the new moons. Say: they are measures of time for people and for Hajj" (Quran 2:189, by meaning).
Mid-month
The full moon and the "white days"
On the 13th, 14th and 15th nights the Moon is at its fullest — the ayyam al-bid, "white days," on which the Prophet ﷺ recommended fasting. The month has its own rhythm: from a thin crescent to a full disc and back.
The year
Twelve months
"Indeed, the number of months with Allah is twelve…" (Quran 9:36). Each lasts 29 or 30 days — as long as a lunar cycle — about 354 days in total. The months are not tied to the seasons; they wander through them.
A special status
The four sacred months
Of the twelve, four are sacred (al-ashhur al-hurum): Muharram, Rajab, Dhul-Qa'dah and Dhul-Hijjah. In them enmity and injustice are especially forbidden — a time of restraint, peace and respect.
The 9th month
Ramadan
The month of fasting, in which the revelation of the Quran began (2:185). Its start is watched for by the hilal, and in its last nights people seek Laylat al-Qadr — the Night of Decree, "better than a thousand months" (surah 97).
Festivals
The two Eids
1 Shawwal — Eid al-Fitr, the festival of completing the fast. 10 Dhul-Hijjah — Eid al-Adha, the festival of sacrifice in the days of Hajj. Both begin with a communal festive prayer and generosity to others.
Why dates "drift"
Minus 11 days a year
The lunar year is about 11 days shorter than the solar one, so Ramadan and the festivals come a little earlier each year — and in roughly 33 years pass through all the seasons. The fast falls on short winter days and long summer ones alike.
Reference
At hand
Structure
The 12 months of the year
On the 10th — Ashura (a day of fasting).
The month of the Prophet's ﷺ birth.
A month of special restraint and peace.
Preparation for Ramadan.
The month of fasting; it holds the Night of Decree.
On the 1st day — the feast of Eid al-Fitr.
Precedes the month of Hajj.
The time of Hajj; on the 10th — Eid al-Adha.
The four sacred months are marked in gold — in them hostility and injustice are especially forbidden.
Glossary
What things are called
The thin young crescent after the new moon. Its appearance marks the start of a new month and sets the start of Ramadan and the feasts.
The 13th, 14th, and 15th of each month, when the Moon is fullest. Fasting on these days is recommended.
Four months — Muharram, Rajab, Dhul-Qa'dah, and Dhul-Hijjah — in which hostility and injustice are especially forbidden.
The most important night of Ramadan, when the revelation of the Qur'an began; «better than a thousand months» (surah 97).
Feasts & days
Key dates
- 1 ShawwalEid al-Fitr — the feast marking the end of the Ramadan fast
- 10 Dhul-HijjahEid al-Adha — the feast of sacrifice, during Hajj
- 10 MuharramAshura — a day of fasting and remembrance
The exact dates differ each year — they are set by sighting the hilal. For decisions about fasting and feasts, turn to your local community or a scholar.