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Islamic calendar

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Wide use Astronomical · Gregorian · Islamic · ISO
Calendar Types
Lunisolar · Solar · Lunar

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Runic · Mesoamerican ( Long Count – Calendar Round)
Christian variants
Julian calendar · Calendar of saints · Eastern Orthodox liturgical calendar · Liturgical year
Rarely used Darian calendar · Discordian calendar
Display types and applications Perpetual calendar · Wall calendar · Economic calendar

The Islamic calendar or Muslim calendar (Arabic: التقويم الهجري; at-taqwīm al-hijrī; Persian: تقویم هجری قمری ‎ taqwīm-e hejri-ye qamari; also called the Hijri calendar) is a lunar calendar used to date events in many predominantly Muslim countries, and used by Muslims everywhere to determine the proper day on which to celebrate Islamic holy days. It is a lunar calendar having 12 lunar months in a year of about 354 days. Because this lunar year is about 11 days shorter than the solar year, Islamic holy days, although celebrated on fixed dates in their own calendar, usually shift 11 days earlier each successive solar year, such as a year of the Gregorian calendar. Islamic years are also called Hijra years because the first year was the year during which the Hijra occurred— Islamic prophet Muhammad's emigration from Mecca to Medina. Thus each numbered year is designated either H or AH, the latter being the initials of the Latin anno Hegirae (in the year of the Hijra).

The current Islamic Year is 1429 AH.


Pre-Islamic calendar

The Arabian predecessor to the Islamic calendar was a lunisolar calendar which used lunar months, but was also synchronized with the seasons by the insertion of an additional, intercalary month, when required. Whether the intercalary month (nasi) was added in the spring like that of the Hebrew calendar or in autumn is debated. It is assumed that the intercalary month was added between the twelfth month (the month of the pre-Islamic Hajj) and the first month ( Muharram) of this pre-Islamic year. The two Rabi' months denote grazing and the modern Meccan rainy season (only slightly less arid than normal), which would promote the growth of grasses for grazing, occurs during autumn. These imply a pre-Islamic year beginning near the autumnal equinox. However, the rainy season after which these months are named may have been different when the names originated (before Muhammad's time) or the calendar may have been imported from another region which did have such a rainy season. Moreover, Arabs had months in which fighting in them was forbidden. So they used the intercalary month to manipulate the time in which these months occur. This is the reason why the Qur'an forbids such manipulation. And the intercalary month was no longer allowed (releasing the calendar from the seasons) by Sura 9, verse 36 (believed to have been revealed about the end of Muhammad's lifetime), which implies a pre-Islamic year beginning near the vernal equinox because that is when the modern lunar year began during his last year.

Annulling intercalation

In the ninth year after the Hijra, as documented in the Qur'an ( 9:36-37), Muslims believe Allah revealed the prohibition of the intercalary month.

The number of months with Allah has been twelve months by Allah's ordinance since the day He created the heavens and the earth. Of these four are known as forbidden [to fight in]; That is the straight usage, so do not wrong yourselves therein, and fight those who go astray. But know that Allah is with those who restrain themselves.

Verily the transposing (of a prohibited month) is an addition to Unbelief: The Unbelievers are led to wrong thereby: for they make it lawful one year, and forbidden another year, of months forbidden by Allah and make such forbidden ones lawful. The evil of their course seems pleasing to them. But Allah guideth not those who reject Faith.

This prohibition was repeated by Muhammad during the last sermon on Mount Arafat which was delivered during the Farewell Pilgrimage to Mecca on 9 Dhu al-Hijja 10 AH:

O People, intercalation is an addition to unbelief, through it [God, Allah] leads the unbelievers astray: they make it permissible one year and forbid it [at their mere convenience] the next one to elude the timing of what God forbade, so that they make permissible that which Allah forbade [fighting in the forbidden months], and forbid that which Allah has made permissible [fighting in other months]. And [now, this year] time has turned the way it was the day God created Heavens and Earth [The intercalary months since the creation of Heavens and Earth have all canceled out (summed up to whole years)]. The year is twelve months, four of them are forbidden, three successive: Dhu al-Qi'dah and Dhu al-Hijjah and Muharram; and the Rajab of Mudar which is between Jumada and Shaban.

Muhammad prohibiting intercalation, illustration of Al-Bīrūnī's The Remaining Signs of Past Centuries (17th century copy of an early 14th century Ilkhanid manuscript).
Muhammad prohibiting intercalation, illustration of Al-Bīrūnī's The Remaining Signs of Past Centuries (17th century copy of an early 14th century Ilkhanid manuscript).

The three successive forbidden months mentioned by Muhammad (months in which battles are forbidden) are Dhu al-Qi'dah, Dhu al-Hijjah, and Muharram, thus excluding an intercalary month before Muharram. The single forbidden month is Rajab. These months were considered forbidden both within the new Islamic calendar and within the old pagan Meccan calendar, although whether they maintained their "forbidden" status after the conquest of Mecca has been disputed among Islamic scholars.

As the number and the position of the intercalary months between 1 AH and 10 AH 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 can be in error by one, two or even three lunar months.


The Islamic months are named as follows:

  1. Muharram محرّم (long form: Muarram ul aram)
  2. Safar صفر (long form: afar ul Muzaffar)
  3. Rabi' al-awwal (Rabī' I) ربيع الأول
  4. Rabi' al-thani (or Rabī' al Thānī, or Rabī' al-Akhir) (Rabī' II) ربيع الآخر أو ربيع الثاني
  5. Jumada al-awwal (Jumādā I) جمادى الأول
  6. Jumada al-thani (or Jumādā al-akhir) (Jumādā II) جمادى الآخر أو جمادى الثاني
  7. Rajab رجب (long form: Rajab al Murajab)
  8. Sha'aban شعبان (long form: Sha'abān ul Moazam)
  9. Ramadan رمضان (or Ramzān, long form: Ramaān ul Mubarak)
  10. Shawwal شوّال (long form: Shawwal ul Mukarram)
  11. Dhu al-Qi'dah ذو القعدة
  12. Dhu al-Hijjah ذو الحجة

Of all the months in the Islamic calendar, Ramaān is the most venerated. Muslims are supposed to abstain from eating, drinking, and sexual intercourse during the daylight hours of this month.

Days of the week

The Islamic week is similar to the Jewish week, as was the medieval Christian week, all of which have numbered weekdays in common. The "first day" of the Islamic week corresponds with Sunday of the planetary week. The Islamic and Jewish weekdays begin at sunset, whereas the medieval Christian and planetary weekdays begin at the following midnight. Muslims gather for worship at a mosque at noon on "gathering day", which corresponds to the sixth day of the Jewish and medieval Christian weeks, and to Friday of the planetary week. ("yaum يوم" means day)

  1. yaum al-ahad يوم الأحد (first day - Sunday) (Urdu, Itwaar اتوار) (Persian: Yek-Shanbeh یکشنبه)
  2. yaum al-ithnayn يوم الإثنين (second day - Monday) (Urdu, Pîr پير) (Persian: Do-Shanbeh, دوشنبه)
  3. yaum ath-thulaathaa' يوم الثُّلَاثاء (third day - Tuesday) (Urdu, Mangl منگل) (Persian: Seh-Shanbeh, سه شنبه)
  4. yaum al-arbia`aa' يوم الأَرْبِعاء (fourth day - Wednesday) (Urdu, Budh بدھ) (Persian: Chahar-Shanbeh, چهارشنبه)
  5. yaum al-khamis يوم الخَمِيس (fifth day - Thursday) (Urdu, Jumahraat جمعرات) (Persian: Panj-Shanbeh, پنجشنبه)
  6. yaum al-jumu`a يوم الجُمُعَة (gathering day - Friday) (Urdu, Jumah جمعہ) (Persian: Jom'eh, جمعه or Adineh آدينه)
  7. yaum as-sabt يوم السَّبْت (sabbath day - Saturday) (Urdu, Hafta ہفتہ) (Persian: Shanbeh, شنبه)


According to Islamic tradition, Abraha, governor of Yemen, then a province of the Christian Kingdom of Aksum (Ethiopia), attempted to destroy the Kaaba with an army which included several elephants. Although the raid was unsuccessful, because it was customary to name a year after a major event which occurred during it, that year became known as the Year of the Elephant, which was also the year that Muhammad was born. (See surat al-Fil.) Although most Muslims equate it with the Western year 570, a minority equate it with 571. Later years were numbered from the Year of the Elephant, whether for the years of the pre-Islamic lunisolar calendar, the lunisolar calendar used by Muhammad before he forbade the intercalary month, or the first few years of the lunar calendar thus created. In 638 (AH 17), the second Caliph Umar began numbering the years of the Islamic calendar from the year of the Hijra, which was postdated AH 1. The first day of the first month (1 Muharram) of that proleptic Islamic year, that is, after the removal of all intercalary months between the Hijra and Muhammad's prohibition of them nine years later, corresponded to July 16, 622 (the actual emigration took place in September). The first surviving attested use of the Hijri calendar is on a papyrus from Egypt in 22 AH, PERF 558.

Upon Muhammad’s arrival at the city of Medina after his Hijra from Mecca, his companions named that year as their first year. It was one of the practices of the people of that time to start their calendar with a certain event. For example, when the army of the ruler Abraha marched to Mecca with elephants to destroy the Kaabah, and then the army was destroyed by Allah according to Islamic tradition, the Arabs named that year as the year of the elephant.

The arrival of Muhammad at the city of Medina was the first victory for Muslims. For the first time Muslims gained the right to run a country based on Islamic teachings led by Muhammad himself. It came naturally to the Muslims at that time to name the year of Muhammad’s arrival at Medina as the first year. This act was not forbidden by Muhammad, and they continued to count their years from the Hijra year onwards.

In the year 17 AH, Abu-Musa al-Asha'ari, one of the officials of the second Caliph Umar in Basrah, reported that a letter from Umar arrived without any date records. This report triggered Umar to introduce a calendar system for Muslims. Umar called the renowned companions such as Ali for a meeting to seek their views on a suitable calendar for Muslims. Some of them suggested to use the Messiah calender which was already followed by many people at that time. There were also some who suggested to start the calendar from the birth of Muhammad. These suggestions were rejected, because the starting dates of those two calendar systems were rather vague.

It was thought that the Islamic calendar should start on an unambiguous date, and a date that was known by many people. There was a suggestion to start on the date of the death of Muhammad, and there were some who suggested to begin with the date of the arrival of Muhammad at Medina. Umar chose to start the calendar with the date of Muhammad’s arrival at Medina, not only because it was a very significant event and was known by almost all Muslims at that time, but more importantly, the companions of Muhammad were already starting their calendar from that date, out of habit.

The second issue to be decided was what would be the first month of the calendar. Some suggested Ramadan, and some suggested the month of Rajab because it was a month much glorified by the Arabs before Islam came. Uthman Ibn Affan suggested to start the calender with the month of Muharram, because it was already the customs of the Arabs at that time to start their year with the month of Muharram, after the return of the pilgrims from their Hajj. This suggestion was agreed by all who were present.

Thus the Islamic calendar started from the month of Muharram in the year of Muhammad’s arrival at the city of Medina, and because of the Hijra event the calendar was named the Hijra calendar.

Observation of Hilal, date calculations, and nonuniform dates among regions

There is at least one recorded incident in the first Islamic century where Muslims in Medina and al-Sham fasted independently upon their respective observations of the lunar crescent (Hilal).

Each month has either 29 or 30 days, but usually in no discernible order. Traditionally, the first day of each month was the day (beginning at sunset) of the first sighting of the lunar crescent (the hilāl) shortly after sunset. If the hilāl was not observed immediately after the 29th day of a month, either because clouds blocked its view or because the western sky was still too bright when the moon set, then the day that began at that sunset was the 30th. Such a sighting had to be made by one or more trustworthy men testifying before a committee of Muslim leaders. Determining the most likely day that the hilāl could be observed was a motivation for Muslim interest in astronomy, which put Islam in the forefront of that science for many centuries.

This traditional practice is still followed in a few parts of the world, like India, Pakistan and Jordan. However, in most Muslim countries astronomical rules are followed which allow the calendar to be determined in advance, which is not the case using the traditional method. Malaysia, Indonesia, and a few others begin each month at sunset on the first day that the moon sets after the sun (moonset after sunset). In Egypt, the month begins at sunset on the first day that the moon sets at least five minutes after the sun.

The moon sets progressively later than the sun for locations further west, thus western Muslim countries are more likely to celebrate some holy days one day earlier than eastern Muslim countries.

Umm al-Qura calendar

The official Umm al-Qura calendar of Saudi Arabia used a substantially different astronomical method until recent years . Before AH 1420 (before April 18, 1999), if the moon's age at sunset in Riyad was at least 12 hours, then the day ending at that sunset was the first day of the month. This often caused the Saudis to celebrate holy days one or even two days before other predominantly Muslim countries, including the dates for the Hajj, which can only be dated using Saudi dates because it is performed in Mecca. During one memorable year during the AH 1380s (the 1970s), different Muslim countries ended the fast of Ramadan on each of four successive days. The celebrations became more uniform beginning in AH 1420. For AH 1420-22, if moonset occurred after sunset at Mecca, then the day beginning at that sunset was the first day of a Saudi month, essentially the same rule used by Malaysia, Indonesia, and others (except for the location from which the hilal was observed). Since the beginning of AH 1423 ( March 16, 2002), the rule has been clarified a little by requiring the geocentric conjunction of the sun and moon to occur before sunset, in addition to requiring moonset to occur after sunset at Mecca. This ensures that the moon has moved past the sun by sunset, even though the sky may still be too bright immediately before moonset to actually see the crescent. Strictly speaking, the Umm al-Qura calendar is intended for civil purposes only. Their makers are well aware of the fact that the first visual sighting of the lunar crescent (hilāl) can occur up to two days after the date calculated in the Umm al-Qura calendar. Since AH 1419 (1998/99) several official hilāl sighting committees have been set up by the government of Saudi Arabia to determine the first visual sighting of the lunar crescent at the begin of each lunar month. Nevertheless, the religious authorities of Saudi Arabia also allow the testimony of less experienced observers and thus often announce the sighting of the lunar crescent on a date when none of the official committees could see the lunar crescent.

This is particularly the case for the most important dates on the Islamic calendar - the beginning and end of Ramadan (the month of the fast) and the beginning of Dhu al-Hijja (the month of the annual pilgrimage to Mecca). If a Muslim male resident (two in the case of the end of Ramadan) sees the new moon on the 29th day of the preceding month, and if this sighting is accepted by the religious authorities, then the new month is judged to have arrived, even though the official Umm al-Qura calendar calls for a 30th day before the new month begins. This can change the actual beginning and/or end of the fast (in the case of Ramadan) or the timing of the pilgrimage to Mecca (in the case of Dhu al-Hijja). This happens occasionally, with the most recent occurrences being in AH 1428 (2007-2008), when the beginning of the months of both Shawwal and Dhu al-Hijja occurred a day earlier than called for in the official Umm al-Qura calendar.

Recently, the Islamic Society of North America, the Fiqh Council of North America and the European Council for Fatwa and Research have announced that they too in future will follow the Umm al-Qura calendar for regulating the Islamic days of observance.

Tabular Islamic calendar

There exists a variation of the Islamic calendar known as the tabular Islamic calendar in which months are worked out by arithmetic rules rather than by observation or astronomical calculation. It has a 30-year cycle with 11 leap years of 355 days and 19 years of 354 days. In the long term, it is accurate to one day in about 2500 years. It also deviates up to about 1 or 2 days in the short term.

Kuwaiti algorithm

Microsoft uses the " Kuwaiti algorithm" to convert Gregorian dates to the Islamic ones. Microsoft claims that it is based on a statistical analysis of historical data from Kuwait but it is in fact a variant of the tabular Islamic calendar.

Notable dates

Important dates in the Islamic (Hijri) year are:

  • 1 Muharram ( Islamic New Year)
  • 10 Muharram ( Day of Ashurah) Anniversary of Moses and the Children of Israel crossing the red sea. Also the date of the martyrdom of Imam Husayn ibn Ali and his followers.)
  • 12 Rabiul Awal ( Milad un Nabi for Sunni Muslims)
  • 17 Rabiul Awal (Milad un Nabi for Isna Ashari Shia Muslims Twelvers)
  • 13 Rajab (Birthday of Imam Ali ibn Abi Talib.)
  • 27 Rajab ( Isra and Miraj)
  • 1 Ramadan (first day of fasting)
  • 19 Ramadan (The day on which Ali ibn Abi Talib was attacked)
  • 21 Ramadan (Imam Ali ibn Abi Talib's death date. He was Muhammad's cousin and son in law and the father of Imam Husayn ibn Ali)
  • 27 Ramadan (Nuzul Al-Qur'an) (17 Ramadan in Malaysia)
  • Last third of Ramadan which includes Laylat al-Qadr
  • 1 Shawwal ( Eid ul-Fitr)
  • 8-10 Dhu al-Hijjah (the Hajj to Mecca)
  • 10 Dhu al-Hijjah (Eid ul-Adha)
  • 18 Dhu al-Hijjah (Eide Ghadire Khum)

Current correlations

For a very rough conversion, multiply the Islamic year number by 0.97, and then add 622 to get the Gregorian year number. An Islamic year will be entirely within a Gregorian year of the same number in the year 20874. The Islamic calendar year of 1429 occurs entirely within the Gregorian calendar year of 2008. Such years occur once every 33 or 34 Islamic years (32 or 33 Gregorian years). More are listed here:

Islamic year within Gregorian year
Islamic Gregorian Difference
1060 1650 590
1093 1682 589
1127 1715 588
1161 1748 587
1194 1780 586
1228 1813 585
1261 1845 584
1295 1878 583
1329 1911 582
1362 1943 581
1396 1976 580
1429 2008 579
1463 2041 578
1496 2073 577
1530 2106 576
1564 2139 575


Many middle eastern coins show the Islamic calendar date, such as this 1993 Egyptian coin which shows both Islamic and Gregorian (1993/1413 - written in Eastern Arabic numerals as ١٤١٣-١٩٩٣).
Many middle eastern coins show the Islamic calendar date, such as this 1993 Egyptian coin which shows both Islamic and Gregorian (1993/1413 - written in Eastern Arabic numerals as ١٤١٣-١٩٩٣).

The Islamic calendar has been used primarily for religious purposes, and has sometimes been used for official purposes as well. Because of its nature as a purely lunar calendar, however, it cannot be used for agricultural purposes and historically Islamic communities have used other calendars for this purpose: the Egyptian calendar was formerly widespread in Islamic countries, and the Iranian calendar and the 1789 Ottoman calendar (a modified Julian calendar) were also used for agriculture in their countries. These local solar calendars have receded in importance with the near-universal adoption of the Gregorian calendar for civil purposes. Saudi Arabia is currently the only Muslim country to use the Islamic calendar as the calendar of daily government business.

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