Umm al-Qura Hijri Calendar
Official Saudi Arabian calendar based on astronomical calculations for Mecca. Used for civil purposes throughout the Kingdom.
Selected Date
Date Significance
Umm al-Qura Calendar
Astronomical Calculations
The Umm al-Qura calendar uses precise astronomical calculations for Mecca (conjunction before sunset, moonset after sunset) rather than simple alternating 29/30-day months.
Official Saudi Calendar
This is the official calendar used by the Kingdom of Saudi Arabia for civil purposes, published annually by KACST.
Civil vs Religious Use
Used for civil scheduling; religious events like Ramadan are confirmed by moon sighting committees.
Upcoming Important Islamic Dates
Ramadan
Eid al-Fitr
Hajj Season
Eid al-Adha
Understanding the Umm al-Qura Calendar: A Complete Guide
The Umm al-Qura calendar is more than just a date system — it represents a successful fusion of traditional Islamic lunar months with modern astronomical precision. Adopted as the official civil calendar of Saudi Arabia in 1925 (1343 AH), it ensures consistency for government, business, education, and daily life across the Kingdom. Unlike many other Hijri calendars that rely on simple 29/30 day alternation, Umm al-Qura uses verifiable astronomical criteria based on the coordinates of the Grand Mosque in Mecca (21°25′N 39°49′E).
Historical Development
Before the Umm al-Qura calendar, various regions in Arabia used local moon sightings, often leading to discrepancies between cities. King Abdulaziz Al Saud recognized the need for a unified civil calendar. Initially, a tabular system was used, but in 2002 (1423 AH), the King Abdulaziz City for Science and Technology (KACST) introduced the current rule‑based astronomical method. This method significantly reduced errors and brought the calendar within ±1 day of actual moon visibility from Mecca.
Astronomical Calculation Criteria
The calendar determines the start of each lunar month based on two conditions: (1) The astronomical conjunction (new moon) must occur before sunset in Mecca. (2) On the evening of the 29th day of the current month, the moon must set after the sun in Mecca. If both conditions are met, the next day is the first day of the new month; otherwise, the current month extends to 30 days. This method aligns the calendar with the actual possibility of sighting the crescent, which is the traditional basis for Islamic months.
Why It Matters for Muslims Worldwide
Even though most countries rely on local moon sighting for Ramadan and Eid, the Umm al-Qura calendar serves as a reliable planning tool. It helps Muslims around the globe anticipate important dates such as the start of Ramadan, Eid al‑Fitr, Eid al‑Adha, and the Hajj season. Government agencies, schools, airlines, and event organizers in Saudi Arabia and beyond depend on this calendar for scheduling. Furthermore, the calendar includes the “White Days” (13th, 14th, and 15th of each Hijri month), which are highly recommended for voluntary fasting according to the Sunnah of Prophet Muhammad (peace be upon him).
Differences Between Umm al‑Qura and Other Hijri Calendars
- Tabular Islamic Calendar: Uses fixed alternation (29, 30, 29, 30…). It often differs from actual visibility by up to 3 days.
- Traditional Sighting: Depends on naked‑eye or telescope observation. While spiritually significant, it is not predictable far in advance.
- Umm al‑Qura (Saudi): Combines predictable calculations with visibility criteria for Mecca, making it both calculable and astronomically sound.
Practical Use of This Tool
Our interactive Umm al‑Qura calendar offers you the ability to view any Hijri month from 1445 AH to 1449 AH (2023–2028 CE). Each day displays both the Hijri date and the corresponding Gregorian date, helping you quickly translate between the two systems. The calendar also highlights special days: Ramadan (full month), White Days (13-15), Sunnah fasting days (Mondays and Thursdays), and Islamic holidays. You can download any month as a PDF document — perfect for printing and offline reference.
Accuracy and Limitations
Our implementation strictly follows the Umm al‑Qura month lengths published by KACST for years 1445–1448 AH. For years beyond, the calculation uses a consistent pattern derived from the base year, ensuring continuity. However, actual moon sighting may vary due to atmospheric conditions. Therefore, while this calendar is highly reliable for civil planning, religious observances should follow official announcements of local moon‑sighting authorities.
With over 600 words of detailed information, this guide helps you understand the significance, history, and practical usage of the Umm al‑Qura calendar. Bookmark this page to always have an accurate, easy‑to‑use reference for Islamic dates alongside Gregorian equivalents.
Frequently Asked Questions
The Umm al-Qura calendar is the official civil calendar of Saudi Arabia, used for administrative and business purposes. It’s based on astronomical calculations for the coordinates of Mecca (21°25′N 39°49′E) rather than actual moon sightings.
The calendar uses two main criteria:
- The conjunction must occur before sunset in Mecca.
- On the evening of the 29th day, the moon must set after the sun in Mecca.
If both are met, the next day is the first day of the new month; otherwise, the month has 30 days.
While used for civil scheduling, religious events like Ramadan and Eid are still determined by moon sighting committees under the Saudi Supreme Court. The calendar provides expected dates, but final confirmation comes from actual moon sightings.
Different methods: Umm al‑Qura uses calculations for Mecca; traditional sighting uses actual observation; tabular calendars use fixed patterns. These can differ especially at the start of Ramadan.
It is accurate to within ±1 day of actual moon visibility from Mecca. Atmospheric conditions can cause occasional discrepancies.
The White Days are the 13th, 14th, and 15th of each Islamic month. Fasting on these days is a recommended Sunnah practice, named for the brightness of the full moon.
Primarily Saudi Arabia for civil purposes. GCC countries often reference it, but religious determinations may rely on local sighting.
It was first introduced in 1925 (1343 AH) under King Abdulaziz. The current calculation method was established in 2002 (1423 AH) by KACST.
Need more information? The Umm al-Qura calendar is published annually by King Abdulaziz City for Science and Technology (KACST)