Prayer time calculation methods: angles and conventions

The signs of the prayer times

Islamic law defines the prayer times with visible signs in the sky, described in the hadith of Jibril, who led the Prophet ﷺ in prayer on two days, and in the hadith of ‘Abdullah ibn ‘Amr reported by Muslim: “The time of Dhuhr is when the sun has passed its zenith and a man’s shadow is like his height, as long as Asr has not come…”. Muslim astronomers translated these signs into angles and formulas, which allow the times to be calculated in advance for any place and date.

• Fajr: begins with true dawn, the horizontal light spreading along the eastern horizon; it is calculated when the sun is between 12° and 20° below the horizon depending on the method.
• Sunrise: the upper edge of the sun appears; calculated at 0.833° below the horizon to account for refraction and the sun’s radius. It ends the time of Fajr.
• Dhuhr: just after the sun passes the meridian (solar noon). Some authorities add a few minutes of precaution.
• Asr: when the shadow of an object equals its length plus its noon shadow (majority), or twice its length (Hanafi).
• Maghrib: when the sun has completely set. Some calendars add a few minutes after sunset.
• Isha: when the twilight disappears, at an angle between 12° and 18°, or a fixed time after Maghrib such as 90 minutes.

The main methods

Why do the angles differ?

True dawn is a gradual phenomenon, and the moment when the light becomes horizontal and spreads along the horizon depends on the clarity of the sky, light pollution and the experience of the observer. Observation campaigns carried out over the decades reached different results: the Egyptian authority uses 19.5°, Morocco 19°, Umm al-Qura 18.5°, the Muslim World League 18°, ISNA in North America 15°, and the UOIF in France 12°. Between 15° and 18° the difference is about 15 to 25 minutes in mid-latitudes, and it grows in summer and further from the equator.

For Isha, some authorities use an angle and others a fixed time after Maghrib, which is easier to apply: Umm al-Qura, Qatar and the Gulf region use 90 minutes, extended to 120 minutes in Ramadan in some countries.

The two opinions for Asr

For the majority of scholars (Maliki, Shafi‘i and Hanbali), Asr begins when the shadow of an object equals its length after the noon shadow; for the Hanafis, when it equals twice its length. The difference ranges from about half an hour in winter to more than an hour in summer. We use the majority opinion by default, and the Hanafi option is available on every page.

High latitudes

North of about 48° in summer, the sun may never go 18° below the horizon: twilight lasts all night, and Fajr and Isha cannot be calculated in the usual way. Like the AlAdhan service, we then apply the “angle-based” rule, which limits the time between sunset and Isha, and between Fajr and sunrise, to a fraction of the night proportional to the angle. Some communities follow other rules, such as the nearest latitude or one seventh of the night; if your mosque does so, follow its calendar.

How we apply this on the site

For each country we choose the method closest to its official or most common calendar, calculate the times with the coordinates of each city and the time zone of the day, and display them to the minute. Because some authorities add minutes of precaution, you may notice a difference of a minute or two with the local adhan. If your mosque follows another method, select it in the settings: your browser will remember it on every page.