The History of the Hijri Calendar: Who Founded It and Why Muharram?
Muslims have used the Hijri calendar for more than fourteen centuries, yet many do not know how it began, who set it up, why its first year is the year of the Hijra or why it starts with Muharram. This article sums up what the history books report.
Before the Hijri calendar
Before Islam, the Arabs already knew the names of the twelve lunar months, including the sacred months, but they did not count years from a fixed event. They dated things by major events, such as the Year of the Elephant, the year the Prophet ﷺ was born. That was enough for a small society, but not once the Muslim state had grown and letters and contracts multiplied.
Umar ibn al-Khattab and the choice of the Hijra
The history books report that the need for a single calendar arose during the caliphate of Umar ibn al-Khattab, after he received letters that gave no year; it is reported that Abu Musa al-Ash'ari wrote to him about this. Umar gathered the Companions and consulted them. Several starting points were proposed, including the Prophet’s ﷺ birth, the beginning of the revelation and his death; they settled on the Hijra, the migration from Mecca to Medina, because it is the event that divides two eras and after which the Muslim state took shape. According to the best-known account this was in the year 17 AH; others say 16 AH.
Why begin with Muharram?
The Prophet ﷺ reached Medina in Rabi' al-Awwal, not in Muharram. But the Companions did not take the day of the Hijra as the starting point: they chose the start of the year in which the Hijra took place, with Muharram as the first month. It is reported that Uthman ibn Affan suggested this because Muharram is when people return from the pilgrimage, a natural start to a new year. That is why 1 Muharram of year 1 falls in July 622, more than two months before the Prophet ﷺ arrived in Medina.
Why did it stay lunar?
The Hijri calendar is purely lunar: no extra month is added to keep it in step with the seasons, because the Quran prohibited the postponement of months (al-nasi’) that used to change the order of the sacred months: “Postponing a sacred month is only an increase in disbelief” (Quran 9:37). As a result, the Hijri year has 354 or 355 days, and the occasions move through all the seasons. The year 1448 AH, for example, has 355 days, from Tuesday 16 June 2026 to Saturday 5 June 2027, and 1449 AH begins on Sunday 6 June 2027 according to Umm al-Qura.
From sighting to calculation
For centuries the start of each month was set by sighting the crescent, and in many countries it still is for acts of worship. Over time, calendars calculated in advance appeared for administrative use; the best known today is Saudi Arabia’s Umm al-Qura calendar, which this site uses. We explain how it works in How the Hijri calendar works: Umm al-Qura explained, and the difference between the two methods in Moon sighting or calculation?
Try it yourself
Convert any date between the two calendars with the date converter, browse the months in the Hijri calendar or see the time left until the Islamic New Year.
Common questions
How many years have passed since the Hijra?
The current Hijri year is 1448, and 1449 begins on Sunday 6 June 2027 according to Umm al-Qura. In solar years, about 1,404 years have passed since the Hijra, because the lunar year is shorter; that is why the Hijri year number (1448) is about 44 higher than the number of solar years since 622 (about 1,404).
Did the Hijra take place on 1 Muharram?
No. 1 Muharram marks the start of the year of the Hijra; the Prophet’s ﷺ arrival in Medina took place in Rabi' al-Awwal of that same year, according to the books of Sirah.
What does “AH” mean?
“AH” comes from the Latin Anno Hegirae, “in the year of the Hijra”; Arabic simply writes the letter ha’, the first letter of “hijri”. Both mark a year counted from the Hijra in the lunar calendar. Gregorian years are counted from the birth of Jesus in the solar calendar.
Is there a solar Hijri calendar?
Yes. It is the official calendar of Iran and counts years from the same Hijra, but in solar years, so its year number is lower. We explain it in the solar Hijri calendar.
From history to today’s tools
If you have an old document dated in the Hijri calendar, convert its date with the converter, bearing in mind that the site covers 1318 to 1500 AH (about 1900 to 2076). Older dates need specialist historical tables, and we do not vouch for their accuracy.