Why Muslims Follow the Islamic (Hijri) Calendar

The Islamic, or Hijri, calendar is a 12-month lunar calendar used to date acts of worship and events such as Ramadan, Hajj, and the two Eids. Many Muslim families use it alongside the Gregorian calendar: one helps track the Islamic year, while the other remains useful for school, work, and civil life.

What the Qur'an says about lunar timekeeping

Qur'an 10:5 points to the moon's phases as a means by which people can calculate years and time. Qur'an 2:189 says that the new moons are measures of time for people and for Hajj. Qur'an 9:36 states that the number of months is twelve and that four are sacred.

These verses establish the religious importance of lunar timekeeping. They do not mean that every printed calendar, conversion table, or modern calculation is itself revealed. Those tools are human ways of applying and organizing the lunar dates.

How an Islamic month is determined

Islamic months follow the lunar cycle. For Ramadan specifically, Sahih al-Bukhari 1909 records the instruction to begin and end the fast with the sighting of the crescent, completing thirty days when the sky prevents a sighting. Muslim communities may differ over local sighting, global sighting, or the role of astronomical calculation, so families should follow a trusted local mosque or recognized authority for worship dates.

Why the dates matter for worship

The Hijri calendar determines when Muslims observe the fast of Ramadan, perform Hajj, celebrate Eid al-Fitr and Eid al-Adha, and recognize the sacred months. Learning the months helps children understand why these occasions move through the seasons when compared with the Gregorian calendar.

How the Hijri era was standardized

The lunar months were known before the Hijri year count was standardized. Egypt's Dar al-Ifta records that Caliph Umar ibn al-Khattab established the Hijri dating era in 637/638 CE after consultation, using the Prophet Muhammad's migration from Makkah to Madinah in 622 CE as its epoch. The event is known as the Hijra, which gives the calendar its name.

The calendar counts years from the Hijra, but the annual cycle begins with Muharram. This distinction helps avoid the common misconception that the migration itself took place on the first day of Muharram; the Prophet's arrival in Madinah occurred later in the year, in Rabi al-Awwal.

Teaching the Hijri calendar accurately

• Use both dates: Mention the Hijri and Gregorian date together so children learn how the calendars relate.
• Connect dates to worship: Mark Ramadan, Hajj, the Eids, and the sacred months without inventing special observances for every new month.
• Expect local differences: A Hijri date can differ by a day between communities because their month-start methods differ.
• Check historical claims: Use a reliable source before assigning a major event to a particular Hijri day.

Practice this week

Use the free Islamic Date Converter to find today's estimated Hijri date, then check it against your local mosque's calendar. Ask your child which Islamic month it is and what, if any, well-established act of worship is connected to that month.

Related Al Noor Kids guides

• Islamic Date Converter
• 30 Islamic games

Sources & References

• Qur'an 10:5 — lunar phases and the reckoning of time
• Qur'an 2:189 — new moons as measures of time and for Hajj
• Qur'an 9:36 — the twelve months
• Sahih al-Bukhari 1909 — sighting the Ramadan crescent
• Egypt's Dar al-Ifta — history of the Hijri calendar
• Encyclopaedia Iranica — calendars in the Islamic period

Editorial note: Religious references were checked conservatively against the linked primary texts. Parenting suggestions are general educational guidance, not a fatwa or medical advice.