Islamic calendar

The Islamic, Muslim, or Hijri calendar (Arabic: التقويم الهجري at-taqwīm al-hijrī) is a lunar calendar consisting of 12 months in a year of 354 or 355 days. It is used (often alongside the Gregorian calendar) to date events in many Muslim countries. It is also used by Muslims to determine the proper days of Islamic holidays and rituals, such as the annual period of fasting and the proper time for the pilgrimage to Mecca.

The Islamic calendar employs the Hijri era whose epoch was retrospectively established as the Islamic New Year of AD 622. During that year, Muhammad and his followers migrated from Mecca to Yathrib (now Medina) and established the first Muslim community (ummah), an event commemorated as the Hijra. In the West, dates in this era are usually denoted AH (Latin: Anno Hegirae, "in the year of the Hijra") in parallel with the Christian (AD) and Jewish eras (AM). In Muslim countries, it is also sometimes denoted as H from its Arabic form ( سَنة هِجْريّة, abbreviated هـ). In English, years prior to the Hijra are reckoned as BH ("Before the Hijra").

Months

Four of the twelve Hijri months are considered sacred: Rajab (7), and the three consecutive months of Dhū al-Qa‘dah (11), Dhu al-Ḥijjah (12) and Muḥarram (1). As the lunar calendar lags behind the solar calendar by about ten days every gregorian year, months of the Islamic calendar fall in different parts of the Gregorian calendar each year. The cycle repeats every 33 lunar years.

No.	Name	Arabic	Meaning	Note
1	Muḥarram	مُحَرَّم	forbidden	A sacred month, so called because battle and all kinds of fighting are forbidden (ḥarām) during this month. Muḥarram includes ‘Āshūrā’, the tenth day.
2	Ṣafar	صَفَر	void	Supposedly named thus because pre-Islamic Arab houses were empty this time of year while their occupants gathered food. Another account relates that they used to loot the houses of their enemies after defeating them in battle, leaving nothing behind.
3	Rabī‘ al-awwal	رَبيع الأوّل	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 the Prophet Muhammad was born.
4	Rabī‘ ath-thānī	رَبيع الثاني	the second spring
5	Jumādá al-ūlá	جُمادى الأولى	the first of parched land	Often considered the pre-Islamic summer. Jumādá may also be related to a verb meaning "to freeze" and another account relates that water would freeze during this time of year.
6	Jumādá al-ākhirah	جُمادى الآخرة	the last of parched land
7	Rajab	رَجَب	respect, honour	This is the second sacred month in which fighting is forbidden. Rajab 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‘bān	شَعْبان	scattered	Marked the time of year when Arab tribes dispersed to find water. Sha‘bān 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 Ramaḍān.
9	Ramaḍān	رَمَضان	burning heat	Burning is related to fasting as in empty stomach one's worldly desire will burn. Supposedly so called because of high temperatures caused by the excessive heat of the sun. Ramaḍān is the most venerated month of the Hijri calendar. During this time, Muslims must fast from pre-dawn till sunset and should give charity to the poor and needy.
10	Shawwāl	شَوّال	raised	She-camels would normally be in calf at this time of year and raise their tails.
11	Dhū al-Qa‘dah	ذو القعدة	the one of truce/sitting	This is a holy month during which war is banned. People are allowed to defend themselves if attacked.
12	Dhū al-Ḥijjah	ذو الحجة	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 sunset of the twelfth, and during which war is banned.

Length of 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 crescent (hilal) 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. However, certain sects and groups, most notably Dawoodi Bohra Muslims and Shia Ismaili Muslims, use a tabular Islamic calendar (see section below) in which odd-numbered months have thirty days (and also the twelfth month in a leap year) and even months have 29.

Days of the week

In Arabic, the "first day" of the week corresponds with Sunday of the planetary week. The Islamic weekdays, like those in the Hebrew and Bahá'í calendars, begin at sunset. The Christian liturgical day, kept in monasteries, begins with vespers (see vesper), which is evening, in line with the other Abrahamic traditions. Christian and planetary weekdays begin at the following midnight. Muslims gather for worship at a mosque at noon on "gathering day" (Yawm al-Jum‘ah, yawm يوم meaning "day") which corresponds with Friday.

Thus "gathering day" is often regarded as the weekly day of rest. This is frequently made official, with many Muslim countries adopting Friday and Saturday (e.g., Egypt, Saudi Arabia) or Thursday and Friday as official weekends, during which offices are closed; other countries (e.g., Iran) choose to make Friday alone a day of rest. A few others (e.g., Turkey, Pakistan, Morocco) have adopted the Saturday-Sunday weekend while making Friday a working day with a long midday break to allow time off for worship.

	Sunday	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday
Name	(Yawm) al-Aḥad	(Yawm) al-Ithnayn	(Yawm) ath-Thulāthā’	(Yawm) al-Arba‘ā’	(Yawm) al-Khamīs	(Yawm) al-Jum‘ah	(Yawm) as-Sabt
Arabic	الأحد	الإثنين	الثلاثاء	الأربعاء	الخميس	الجمعة	السبت
Meaning	First day	Second day	Third day	Fourth day	Fifth day	Gathering day	Day of Rest

Converting Hijri to Gregorian date or vice versa

Conversions may be made online, by using the Tabular Islamic calendar, or, for greatest accuracy (one day in 15,186 years), via the Jewish calendar. Theoretically, the days of the months correspond in both calendars if the displacements which are a feature of the Jewish system are ignored. The table below gives, for nineteen years, the Muslim month which corresponds to the first Jewish month.

Year AD Year AH Muslim month 2011 1432 5 2012 1433 5 2013 1434 5 2014 1435 6 2015 1436 6 2016 1437 7 2017 1438 7 2018 1439 7 2019 1440 8 2020 1441 8

Year AD Year AH Muslim month 2021 1442 8 2022 1443 9 2023 1444 9 2024 1445 10 2025 1446 10 2026 1447 10 2027 1448 11 2028 1449 11 2029 1450 11

This table may be extended since every nineteen years the Muslim month number increases by seven. When it goes above twelve, subtract twelve and add one to the year AH. From AD412 to AD632 inclusive the month number is 1 and the calculation gives the month correct to a month or so. AD622 corresponds to BH1 and AH1. For earlier years, year BH = (623 or 622) – year AD).