How We Calculate Ramadan Dates

Every Ramadan date on ramadanclock.com is either an official date announced by a religious authority or an expected date based on the published Umm al-Qura calendar and astronomical data. This page explains how each country decides when Ramadan begins, how our countdown works, and how we estimate sehri, iftar and fasting hours.

Last reviewed: 18 October 2026

Why Ramadan starts on different days

Ramadan begins when the new crescent moon (hilal) marks the start of the ninth month of the Islamic calendar. Some countries rely on astronomical calculation, while others wait for the crescent to be seen with the eye on the 29th evening of Sha’ban. Because the new moon is usually visible first in western regions, countries further east often start a day later. This is why Ramadan, and Eid al-Fitr, can fall on different days in Saudi Arabia, Turkey, Indonesia, Iran and Bangladesh in the same year.

How each country sets the date

Country or communityWho decidesMethod
Saudi Arabia and most Gulf statesSupreme Court of Saudi Arabia, Umm al-Qura calendarCrescent sighting reports, with the Umm al-Qura calendar as the civil calendar
Turkey and Turkish mosques in EuropeDiyanet (Presidency of Religious Affairs)Astronomical calculation, following the 2016 International Hijri Calendar Union Congress in Istanbul. Dates are published years in advance
Indonesia (government)Ministry of Religious Affairs (Kemenag), sidang isbatCrescent sighting with the MABIMS criteria (crescent at least 3° high and 6.4° from the sun)
Indonesia (Muhammadiyah)MuhammadiyahKalender Hijriah Global Tunggal (KHGT), one global calculated calendar
IranMoon Sighting Headquarters (Setad-e Esteghlal) of the Office of the Supreme LeaderLocal crescent sighting
BangladeshNational Moon Sighting Committee, Islamic Foundation BangladeshLocal crescent sighting
PakistanCentral Ruet-e-Hilal CommitteeLocal crescent sighting
North AmericaVaries by mosque; the Fiqh Council of North America uses calculationCalculation or sighting, depending on the community
United Kingdom and EuropeVaries by mosque and organisationMany follow Saudi Arabia, others follow local sighting or Diyanet

How our countdown works

  • Base dates: the countdown uses a table of expected 1 Ramadan and Eid al-Fitr dates from 2026 to 2037, based on the Umm al-Qura calendar.
  • Country adjustments: where a country usually starts one day later because of local sighting, the countdown adds that day. Country buttons on each page let you switch between dates.
  • Official calendars: where an authority has already published its dates, such as Diyanet in Turkey or Muhammadiyah in Indonesia, the page uses those dates.
  • Your local time: the countdown runs on your own device clock and counts to the start of the day (00:00) in your time zone, so it works anywhere in the world.

How we estimate sehri, iftar and fasting hours

Fasting runs from dawn (Fajr) to sunset (Maghrib). We calculate sunrise, sunset and dawn with the standard NOAA solar position formulas, using each city’s latitude and longitude. Dawn is defined by how far the sun is below the horizon, and different authorities use different angles:

RegionFajr angle we useBased on
Saudi Arabia and Gulf18.5°Umm al-Qura
Turkey, Pakistan, Bangladesh, Afghanistan18°Diyanet and the University of Islamic Sciences, Karachi
Indonesia20°Kemenag
Iran17.7° (Maghrib 4.5°)Institute of Geophysics, University of Tehran
North America, UK and Europe15° to 18°Common local practice

Sunset is taken when the top of the sun touches the horizon, and we add a few minutes of caution (ihtiyat) for iftar, as most published timetables do. All times are rounded to 5 minutes. Our times are estimates and can differ by a few minutes from your local mosque or official timetable, which you should always follow for fasting.

Expected dates and confirmed dates

Until an authority makes its announcement, we label dates as “expected” or “estimated”. When the announcement is made, we update the page, change the label to the confirmed date and record the change in our Corrections and Updates Log.

Spotted a wrong date?

If a date on our site does not match the announcement in your country, please tell us through the Contact page, with a link to the announcement if possible. We check every report and correct confirmed errors as quickly as we can.