Islamic calendar

The Islamic calendar or Muslim calendar (: التقويم الهجري; at-taqwīm al-hijrī; : تقویم هجري قمری ‎ taqwīm-e hejri-ye qamari; also called the Hijri calendar) is the used to date events in many predominantly  countries, and used by Muslims everywhere to determine the proper day on which to celebrate Islamic holy days. It is a 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. Islamic years are also called Hijra years because the was the year during which the  occurred&mdash; 's emigration from  to. Thus each numbered year is designated either H or AH, the latter being the initials of the anno Hegirae (in the year of the Hijra).

The current Islamic Year is 1428 AH.

Pre-Islamic calendar
The Arabian predecessor to the Islamic calendar was a which used lunar months, but was also synchronized with the seasons by the insertion of an additional,, when required. Whether the intercalary month (nasi) was added in the spring like that of the or in autumn is debated. It is assumed that the intercalary month was added between the twelfth month (the month of the pre-Islamic ) and the first month 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. 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. On the other hand, the forbids the intercalary month (releasing the calendar from the seasons) by, verse 36 (believed to have been revealed about the end of Muhammad's lifetime), which implies a pre-Islamic year beginning near the  because that is when the modern lunar year began during his last year.

Months
The Islamic months are named as follows:
 * 1)  محرّم (long form: Muarram ul aram)
 * 2)  صفر (long form: afar ul Muzaffar)
 * 3)  (Rabī' I) ربيع الأول
 * 4)  (or Rabī' al Thānī, or Rabī' al-Akhir) (Rabī' II) ربيع الآخر أو ربيع الثاني
 * 5)  (Jumādā I) جمادى الأول
 * 6)  (or Jumādā al-akhir) (Jumādā II) جمادى الآخر أو جمادى الثاني
 * 7)  رجب (long form: Rajab al Murajab)
 * 8)  شعبان (long form: Sha'abān ul Moazam)
 * 9)  رمضان (or Ramzān, long form: Ramaān ul Mubarak)
 * 10)  شوّال (long form: Shawwal ul Mukarram)
 * 11)  ذو القعدة
 * 12)  ذو الحجة

Of all the months in the Islamic calendar, is the most venerated. Between dawn and sunset, s are supposed to abstain from eating, drinking, and sexual intercourse in accordance with the that lasts throughout the entire month of the same name.

Days of the week
The Islamic week is derived from 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 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.


 * 1) yaum al-ahad يوم الأحد (first day - Sunday) (, 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)

Annulling intercalation
In the ninth year after the Hijra, as documented in the (9:36-37),  revealed the prohibition of the  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 on  which was delivered during the  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.

The three successive forbidden months mentioned by Muhammad (months in which battling is forbidden) are, , and , thus excluding an intercalary month before Muharram. The single forbidden month is. 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 has been disputed among Islamic scholars.

Numbering the years
According to Islamic tradition,, governor of , then a province of the  , attempted to destroy the  with an army which included several s. 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 , which was also the year that Muhammad  was born. (See t .) Although most Muslims equate it with the 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 began numbering the years of the Islamic calendar from the year of the, 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, (the actual emigration took place in September). The first surviving attested use of the Hijri calendar is on a from  in 22 AH,.

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 and  fasted independently upon their respective observations of the lunar crescent (Hilal).

Each 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 ) 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, 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, and. 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. ,, and a few others begin each month at sunset on the first day that the moon sets after the sun (moonset after sunset). In, 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 day one day earlier than eastern Muslim countries.

Umm al-Qura calendar
The official calendar of  used a substantially different astronomical method until recent years. Before AH 1420 (before, ), if the moon's age at sunset in was at least 12 hours, then the day ending at that sunset was the first day of the month. This often caused the s to celebrate holy days one or even two days before other predominantly Muslim countries, including the dates for the, 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, 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 to determine the first visual sighting of the lunar crescent at the begin of each lunar month. Nevertheless, the religious authorities of 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 Makkah). 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 Makkah (in the case of Dhu al-Hijja). This happens occasionally, with the most recent occurrences being in AH 1427 (2006-2007), when the beginning of the months of both Ramadan and Dhu al-Hijja occurred a day earlier than called for in the official Umm al-Qura calendar.

Recently, the, the and the  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 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
uses the "" 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.

Notable dates
Important dates in the Islamic (Hijri) year are:
 * 1 Muharram
 * 10 Muharram (, Anniversary of the martyrdom of Imam and his followers.)
 * 12 Rabiul Awal ( for Sunni Muslims)
 * 17 Rabiul Awal (Milad un Nabi for Shia Muslims)
 * 13 Rajab (Birthday of Imam .)
 * 27 Rajab
 * 1 Ramadan (first day of fasting)
 * 21 Ramadan (Imam 's death date. He was 's cousin and son in law and the father of Imam )
 * 27 Ramadan (Nuzul Al-Qur'an) (17 Ramadan in )
 * Last third of Ramadan which includes
 * 1 Shawwal
 * 8-10 Dhu al-Hijjah (the to )
 * 10 Dhu al-Hijjah.

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 will occur 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:

Uses
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, however, it cannot be used for agricultural purposes and historically Islamic communities have used other calendars for this purpose: the was formerly widespread in Islamic countries, and the  and the 1789  (a modified Julian calendar) were also used for agriculture in their countrues. These local solar calendars have receded in importance with the near-universal adoption of the Gregorian calendar for civil purposes. is currently the only Islamic country to use the Islamic calendar as the calendar of daily government business.

Date converters

 * Gregorian-Hijri Dates Converter (and vice-versa)
 * Islamic-Western Calendar Converter (Based on the Arithmetical or Tabular Calendar)
 * al-Islam.com date converter