Ramadan Calendar Calculator
Calculate ramadan calendar easily with our free tool. Get practical results, tips, and comparisons for everyday decisions.
Reviewed for accuracy by Daniel Agrici, Founder & Lead Developer
Ramadan Calendar Calculator
Calculator
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Formula: Fajr = Solar Noon − (1/15) × arccos[(sin(-18°) − sin(lat)sin(dec)) / (cos(lat)cos(dec))]
Worked example — Suhoor ends: ~5:00 AM | Iftar: ~6:22 PM | Fast: ~13h 10min
Formula
Fajr = Solar Noon − (1/15) × arccos[(sin(-18°) − sin(lat)sin(dec)) / (cos(lat)cos(dec))]
Prayer and fasting times are calculated using the sun's position. Fajr (dawn) occurs when the sun is 18° below the horizon. Maghrib (sunset) occurs at the geometric sunset. These depend on latitude, longitude, day of year, and the sun's declination.
Worked Examples
Example 1: Fasting Schedule in Makkah (Day 1 of Ramadan)
Problem:Calculate Suhoor and Iftar times for Makkah (lat 21.42°N, lng 39.83°E, UTC+3) on the first day of Ramadan.
Solution:Solar declination for ~March 18: ~-1.5° Fajr angle: -18° below horizon Fajr (Suhoor end): ~5:10 AM Sunrise: ~6:15 AM Maghrib (Iftar): ~6:20 PM Fast duration: ~13 hours 10 minutes
Result:Suhoor ends: ~5:00 AM | Iftar: ~6:22 PM | Fast: ~13h 10min
Example 2: Fasting Schedule in London (Day 15 of Ramadan)
Problem:Calculate fasting times for London (lat 51.51°N, lng -0.13°W, UTC+0) on day 15 of Ramadan (~early April).
Solution:Solar declination for ~April 1: ~4.5° Fajr at 51.5°N latitude: ~4:30 AM Sunrise: ~6:30 AM Maghrib: ~7:40 PM Fast duration: ~15 hours 10 minutes Note: London fasting hours are longer due to higher latitude
Result:Suhoor ends: ~4:20 AM | Iftar: ~7:42 PM | Fast: ~15h 10min
Frequently Asked Questions
How are Suhoor and Iftar times calculated?
Suhoor and Iftar times are calculated based on the position of the sun relative to the horizon at your specific geographic location. Suhoor (the pre-dawn meal) ends at Fajr time, which is when the sun is approximately 18 degrees below the eastern horizon (astronomical twilight begins). Many scholars recommend stopping eating 10-15 minutes before Fajr as a precaution. Iftar (the meal to break the fast) begins at Maghrib time, which is when the sun fully sets below the western horizon. Some communities add a 1-3 minute delay after sunset as a safety margin. The exact times vary daily because the sun's path changes throughout the month, and they differ significantly by geographic location and time of year.
Why do fasting hours vary by location during Ramadan?
Fasting hours vary dramatically by location because they depend on geographic latitude. Near the equator, day length remains relatively constant at about 12 hours year-round, resulting in consistent fasting durations of approximately 12-13 hours. At higher latitudes, day length varies greatly with the seasons. When Ramadan falls in summer months at northern latitudes, fasting can last 18-20 hours (as in Scandinavia or northern Canada). Conversely, when Ramadan occurs in winter at these locations, fasting might only be 8-9 hours. Locations very close to the poles may experience perpetual daylight or darkness, in which case Islamic scholars generally advise following the times of the nearest city with distinguishable day and night, or following Makkah's times.
What is the Islamic ruling on fasting at extreme latitudes?
At extreme latitudes (above 60 degrees) where the sun may not set or rise for extended periods, Islamic scholars have provided several opinions. The majority opinion from the Islamic Fiqh Council is to follow the prayer and fasting times of the nearest city where day and night are clearly distinguishable. Another scholarly opinion suggests following the times of Makkah al-Mukarramah, since it is the mother of all cities in Islamic tradition. A third opinion allows following the last normal day-night cycle before continuous daylight or darkness began. The European Council for Fatwa and Research recommends that Muslims in these areas should follow the nearest country where fasting hours are manageable, typically defined as having distinct dawn and dusk within a 24-hour period.
How does the Ramadan calendar shift each year?
Ramadan shifts approximately 10 to 11 days earlier each year on the Gregorian calendar because the Islamic calendar is a lunar calendar with 354 or 355 days per year, compared to the 365 or 366 days in the Gregorian solar calendar. This means Ramadan cycles through all seasons over approximately 33 years. In summer months, fasting hours are longer in the Northern Hemisphere, while in winter they are shorter. The exact start date of Ramadan is determined either by the physical sighting of the new crescent moon (hilal) or by astronomical calculations, depending on the methodology followed by different Muslim communities and countries. This is why the start date may differ by one or two days between regions.
What is the difference between Fajr angle methods used worldwide?
Different Islamic organizations use different sun depression angles for calculating Fajr time, which affects when fasting begins. The Muslim World League uses 18 degrees below the horizon for Fajr and 17 degrees for Isha. The Egyptian General Authority of Survey uses 19.5 degrees for Fajr and 17.5 degrees for Isha. The Islamic Society of North America (ISNA) uses 15 degrees for both Fajr and Isha. The University of Islamic Sciences, Karachi uses 18 degrees for Fajr and 18 degrees for Isha. The Umm al-Qura method used in Saudi Arabia uses a fixed 18.5 degrees for Fajr. These differences can result in Fajr times varying by 15-30 minutes between methods at the same location, which is why Muslims should follow the convention adopted by their local Islamic authority.
What is the difference between business days and calendar days?
Calendar days include every day. Business days (or working days) exclude weekends (Saturday and Sunday) and public holidays. A 10-business-day deadline is typically 14 calendar days. Legal and financial deadlines often specify which type applies.
What is the difference between the Julian and Gregorian calendars?
The Julian calendar (introduced by Julius Caesar in 46 BC) assumed a 365.25-day year, adding a leap day every 4 years. The Gregorian calendar (1582) corrected the drift by skipping 3 leap years every 400 years. Most of the world now uses the Gregorian calendar.
References
Reviewed for accuracy by Daniel Agrici, Founder & Lead Developer · Editorial policy
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