Islamic calendar

The Hijri calendar, also known in English as the Islamic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 or 355 days. It is used to determine the proper days of Islamic holidays and rituals, such as the annual fasting and the annual season for the great pilgrimage. In almost all countries where the predominant religion is Islam, the civil calendar is the Gregorian calendar, with Syriac month-names used in the Levant and Mesopotamia, but the religious calendar is the Hijri one.
This calendar enumerates the Hijri era, whose epoch was established as the Islamic New Year in 622 CE. During that year, Muhammad and his followers migrated from Mecca to Medina and established the first Muslim community, an event commemorated as the Hijrah. In the West, dates in this era are usually denoted AH. In Muslim countries, it is also sometimes denoted as H from its Arabic form. In English, years prior to the Hijra are denoted as BH.
Since 26 June 2025 CE,. In the Gregorian calendar reckoning, 1447 AH runs from 26 June 2025 to approximately 15 June 2026.

History

Pre-Islamic calendar

For central Arabia, especially Mecca, there is a lack of epigraphical evidence but details are found in the writings of Muslim authors of the Abbasid era. Inscriptions of the ancient South Arabian calendars reveal the use of a number of local calendars. Some of these South Arabian calendars followed the lunisolar system. Both al-Biruni and al-Mas'udi suggest that the ancient Arabs used the same month names as the Muslims, though they also record other month names used by the pre-Islamic Arabs.
The Islamic tradition is unanimous in stating that Arabs of Tihamah, Hejaz, and Najd distinguished between two types of months, permitted and forbidden months. The forbidden months were four months during which fighting is forbidden, listed as Rajab and the three months around the pilgrimage season, Dhu al-Qa‘dah, Dhu al-Hijjah, and Muharram. A similar if not identical concept to the forbidden months is also attested by Procopius, where he describes an armistice that the Eastern Arabs of the Lakhmid al-Mundhir respected for two months in the summer solstice of 541 CE. However, Muslim historians do not link these months to a particular season. The Qur'an links the four forbidden months with Nasī, a word that literally means "postponement". According to Muslim tradition, the decision of postponement was administered by the tribe of Kinanah, by a man known as the al-Qalammas of Kinanah and his descendants.
Different interpretations of the concept of Nasī have been proposed. Some scholars, both Muslim and Western, maintain that the pre-Islamic calendar used in central Arabia was a purely lunar calendar similar to the modern Islamic calendar. According to this view, Nasī is related to the pre-Islamic practices of the Meccan Arabs, where they would alter the distribution of the forbidden months within a given year without implying a calendar manipulation. This interpretation is supported by Arab historians and lexicographers, like Ibn Hisham, Ibn Manzur, and the corpus of Qur'anic exegesis.
This is corroborated by an early Sabaic inscription, where a religious ritual was "postponed" due to war. According to the context of this inscription, the verb ns'’ has nothing to do with intercalation, but only with moving religious events within the calendar itself. The similarity between the religious concept of this ancient inscription and the Qur'an suggests that non-calendaring postponement is also the Qur'anic meaning of Nasī. The Encyclopaedia of Islam concludes "The Arabic system of can only have been intended to move the Hajj and the fairs associated with it in the vicinity of Mecca to a suitable season of the year. It was not intended to establish a fixed calendar to be generally observed." The term "fixed calendar" is generally understood to refer to the non-intercalated calendar.
Others concur that it was originally a lunar calendar, but suggest that about 200 years before the Hijra it was transformed into a lunisolar calendar containing an intercalary month added from time to time to keep the pilgrimage within the season of the year when merchandise was most abundant. This interpretation was first proposed by the medieval Muslim astrologer and astronomer Abu Ma'shar al-Balkhi, and later by al-Biruni, al-Mas'udi, and some western scholars. This interpretation considers Nasī to be a synonym to the Arabic word for "intercalation". The Arabs, according to one explanation mentioned by Abu Ma'shar, learned of this type of intercalation from the Jews. The Jewish Nasi was the official who decided when to intercalate the Jewish calendar. Some sources say that the Arabs followed the Jewish practice and intercalated seven months over nineteen years, or else that they intercalated nine months over 24 years; there is, however, no consensus among scholars on this issue.

Prohibiting Nasī'

is interpreted to signify either the postponement of the pre-Islamic month of Hajj, or the practice of intercalation periodic insertion of an additional month to reset the calendar into accordance with the seasons.
In the tenth year of the Hijra, as documented in the Qur'an, Muslims believe God revealed the "prohibition of the Nasī.
The prohibition of Nasī' would presumably have been announced when the intercalated month had returned to its position just before the month of Nasi' began. If Nasī' meant intercalation, then the number and the position of the intercalary months between AH 1 and AH 10 are uncertain; western calendar dates commonly cited for key events in early Islam such as the Hijra, the Battle of Badr, the Battle of Uhud and the Battle of the Trench should be viewed with caution as they might be in error by one, two, three or even four lunar months. This prohibition was mentioned by Muhammad during the farewell sermon which was delivered on 9 Dhu al-Hijjah AH 10 on Mount Arafat during the farewell pilgrimage to Mecca.
The three successive sacred months mentioned by Muhammad are Dhu al-Qa'dah, Dhu al-Hijjah, and Muharram, months 11, 12, and 1 respectively. The single forbidden month is Rajab, month 7. These months were considered forbidden both within the new Islamic calendar and within the old pagan Meccan calendar.

Days of the week

Traditionally, the Islamic day begins at sunset and ends at the next sunset. Each Islamic day thus begins at nightfall and ends at the end of daylight.
The days in the seven-day week are, with the exception of the last two days, named after their ordinal place in the week.
On the sixth day of the week, the "gathering day", Muslims assemble for the Friday-prayer at a local mosque at noon. The "gathering day" is often regarded as the weekly day off. This is frequently made official, with many Muslim countries adopting Friday and Saturday or Thursday and Friday as official weekends, during which offices are closed; other countries choose to make Friday alone a day of rest. A few others have adopted the Saturday-Sunday weekend while making Friday a working day with a long midday break to allow time off for worship.

No.	Name	Arabic	Meaning	English equivalent
1	al-ʾAḥad		the One	Saturday night and Sunday daytime
2	al-Ithnayn		the Second	Sunday night and Monday daytime
3	ath-Thulāthāʾ		the Third	Monday night and Tuesday daytime
4	al-ʾArbiʿāʾ		the Fourth	Tuesday night and Wednesday daytime
5	al-Khamīs		the Fifth	Wednesday night and Thursday daytime
6	al-Jumʿah		the Gathering	Thursday night and Friday daytime
7	as-Sabt		the Rest	Friday night and Saturday daytime

Months

Each month of the Islamic calendar commences on the birth of the new lunar cycle. Traditionally, this is based on actual observation of the moon's crescent, marking the end of the previous lunar cycle and hence the previous month, thereby beginning the new month. Consequently, each month can have 29 or 30 days depending on the visibility of the Moon, astronomical positioning of the Earth and weather conditions.
Four of the twelve Hijri months are considered sacred: , and the three consecutive months of , and , in which battles are forbidden.

No.	Name	Arabic	Meaning	Note
1	Muharram\|	ٱلْمُحَرَّم	forbidden	A sacred month, so called because battle and all kinds of fighting are forbidden during this month. Muharram includes Ashura, the tenth day.
2	Safar\|	صَفَر	void	Supposedly named this because pre-Islamic Arab houses were empty this time of year while their occupants gathered food.
3	Rabi' al-Awwal\|	رَبِيع ٱلْأَوَّل	the first spring	Also means to graze, because cattle were grazed during this month. Also a very holy month of celebration for many Muslims, as it was the month Muhammad was born.
4	Rabi' al-Thani\| or	رَبِيع ٱلثَّانِي or رَبِيع ٱلْآخِر	the second spring, the last spring
5	Jumada al-awwal\|	جُمَادَىٰ ٱلْأُولَىٰ	the first of parched land	Often considered the pre-Islamic summer. may also be related to a verb meaning "to freeze" and another account relates that water would freeze during this time of year.
6	Jumada al-Thani\| or	جُمَادَىٰ ٱلثَّانِيَة or جُمَادَىٰ ٱلْآخِرَة	the second of parched land, the last of parched land
7		رَجَب	respect, honour	This is the second sacred month in which fighting is forbidden. may also be related to a verb meaning "to remove", so called because pre-Islamic Arabs would remove the heads of their spears and refrain from fighting.
8	Sha'ban\|	شَعْبَان	scattered	Marked the time of year when Arab tribes dispersed to find water. may also be related to a verb meaning "to be in between two things". Another account relates that it was called thus because the month lies between Rajab and Ramadan.
9	Ramadan \|	رَمَضَان	burning heat	Burning is related to fasting as with an empty stomach one's worldly desire will burn. Supposedly so called because of high temperatures caused by the excessive heat of the sun. is the most venerated month of the Hijri calendar. During this time, Muslims must fast and not do anything sinful from pre-dawn until sunset and should give charity to the poor and needy.
10	Shawwal\|	شَوَّال	raised	Female camels would normally be in calf at this time of year and raise their tails. At the first day of this month, the Eid al-Fitr, "Festival of Breaking the Fast" begins, marking the end of fasting and the end of Ramadan.
11	Dhu al-Qadah\|	ذُو ٱلْقَعْدَة	the one of truce/sitting	This is a holy month during which war is banned. People are allowed to defend themselves if attacked.
12	Dhu al-Hijjah\|	ذُو ٱلْحِجَّة	the one of pilgrimage	During this month Muslim pilgrims from all around the world congregate at Mecca to visit the Kaaba. The Hajj is performed on the eighth, ninth and the tenth of this month. Day of Arafah takes place on the ninth of the month. Eid al-Adha, the "Festival of the Sacrifice", begins on the tenth day and ends on the thirteenth, and this is a fourth holy month during which war is banned.