MUHAMMADIYAH.OR.ID, YOGYAKARTA – Muhammadiyah Chairperson of Religious Opinion and Tajdid Syamsul Anwar emphasized the importance of the Unified Global Hijri Calendar (UGHC) in a seminar at Universitas ‘Aisyiyah Yogyakarta on Wednesday, June 25. Syamsul said the calendar aims to unify the start of the Islamic months around the world, helping strengthen Muslim unity in a globalized era.
Syamsul explained that the UGHC is based on hisab, or astronomical calculations, to determine the beginning of each Hijri month. This method offers a consistent global standard, different from early Islamic calendars that used basic counting methods (al-taqwim al-‘adadi) without tracking the actual movement of the moon and sun. As a result, early calendars often misaligned with moon sightings, sometimes placing the start of Ramadan a day or two off.
“The old calendar system always made Ramadan 30 days even though the Prophet fasted either 29 or 30 days depending on the moon,” explained Syamsul.
While many Muslims later adopted moon sighting (rukyat), Syamsul noted that relying on local calendars still leads to differences between countries. He referred to a recommendation from the 11th Islamic Summit, which called for a unified calendar to help improve the image and unity of the global Muslim community.
“In today’s globalized world, the world is like a small village. A shared calendar is urgently needed to strengthen our Islamic brotherhood,” said Syamsul.
Syamsul added that from a religious perspective, there’s no specific requirement for one type of calendar, but the UGHC is in line with the goals of Islamic law (maqashid syariah). Citing Imam al-Shatibi, he said that religious decisions can be based on general principles drawn from various sources.
He also referred to several verses from the Qur’an that emphasize unity, such as: “ Indeed, this religion of yours is [only] one” (Al-Anbya: 92) and “We have sent you [O Prophet] only as a deliverer of good news and a warner to all of humanity” (Saba: 28).
A hadith from the Prophet Muhammad (PBUH) also supports shared observance: “The fast is the day the people fast, the breaking of the fast is the day the people break their fast, and the sacrifice is the day the people sacrifice.”
For Syamsul, the UGHC is not just a matter of how to count dates. It’s a way to bring Muslims together in shared worship and strengthen their identity in today’s interconnected world.
“This is a step toward unity in worship and reinforcing our Islamic identity,” said Syamsul.
