Isbat Session to Be Held Tomorrow, Potential for Different Idul Fitri Dates in 2026
The Ministry of Religious Affairs will hold the Isbat session tomorrow, Thursday (19 March), to determine the establishment of 1 Syawal 1447 Hijriah. The outcome of the Isbat session is eagerly awaited by Muslims in Indonesia as it determines when the Idul Fitri 1447 Hijriah holiday, or Lebaran 2026, will fall.
The Isbat session will be conducted at the HM Rasjidi Auditorium in the Ministry of Religious Affairs office on Jl MH Thamrin, Central Jakarta, at 4:00 PM WIB. This location differs from the Isbat session for 1 Ramadan 1447 Hijriah, which was held at the Borobudur Hotel.
Director General of Islamic Guidance at the Ministry of Religious Affairs, Abu Rokhmad, explained that the Isbat session for 1 Syawal 1447 Hijriah involves various parties, including astronomy experts from the Meteorology, Climatology, and Geophysics Agency (BMKG), the National Research and Innovation Agency (BRIN), planetariums, observatories, representatives of Islamic community organisations, and other related institutions.
There are two main methods to be used in the Isbat session: hisab (astronomical calculation) and rukyat (sighting of the new moon). If the new moon is observed on 19 March 2026 meeting the government’s criteria, then Idul Fitri 1447 Hijriah will fall on 20 March 2026; if not, it will be 21 March 2026.
Government and NU Calendar
The government has predicted that Idul Fitri 1447 Hijriah will fall on Saturday, 21 March 2026. This has been established in the Indonesian Hijriah Calendar for 2026 issued by the Ministry of Religious Affairs.
Similar information is also included in the 2026 Almanac released by the Falakiyah Board of the Nahdlatul Ulama (NU) Bojonegoro District Executive. However, the final decision has not yet been determined as it awaits the Isbat session on 19 March 2026.
BRIN
In addition to the government, BRIN has also issued a prediction for Idul Fitri 1447 Hijriah on 21 March 2026.
Researcher from the BRIN Space Research Centre, Thomas Djamaluddin, stated that astronomically, at Maghrib time in the Southeast Asia region on Thursday (19 March), the position of the new moon does not yet meet the new MABIMS criteria of the Ministers of Religious Affairs of Brunei, Indonesia, Malaysia, and Singapore.
The MABIMS criteria for determining the start of the Hijriah month stipulate a minimum visibility of the new moon at 3 degrees and a minimum geocentric elongation angle of 6.4 degrees.
“At Maghrib on 19 March 2026 in the Southeast Asia region, the new moon’s position does not yet meet the new MABIMS criteria, so 1 Syawal 1447 = 21 March 2026,” said Thomas in his 2025 blog post.
He added that using other criteria, such as those used by Turkey, the result could differ.
“Thus, according to Turkish criteria, 1 Syawal 1447 = 20 March 2026,” he added.
BMKG
The Meteorology, Climatology, and Geophysics Agency (BMKG) has revealed data on the observation of the new moon on 19 March 2026, with the altitude at sunset estimated to range from 0.91 degrees in Merauke, Papua, to 3.13 degrees in Sabang, Aceh.
Meanwhile, the geocentric elongation is estimated to be in the range of 4.54 degrees in Waris, Papua, to 6.1 degrees in Banda Aceh.
Based on this data and the MABIMS criteria, the new moon is likely not visible on 19 March 2026, so the month of Ramadan will be completed to 30 days, and Idul Fitri 1447 Hijriah will fall on 21 March 2026.
Muhammadiyah on 20 March 2026
Differing from the predictions of the government, BRIN, and BMKG, Muhammadiyah has already determined Idul Fitri 1447 Hijriah on 20 March 2026.
This determination is outlined in the Central Leadership Memorandum of Muhammadiyah Number 2/MLM/1.0/E/2025 on the Determination of Hisab Results for Ramadan, Syawal, and Zulhijah 1447 H.
This difference often occurs every year due to the dissimilarity in methods for determining the start of the Hijriah month.