How Sabīl calculates prayer times

Sabīl does not download a timetable. It works the times out on your phone, from your place and the date, with an open-source library called adhan. This page sets out what that calculation does, as the code has it.

It does not say which method or angle is right, and it gives no ruling about when a prayer may be prayed. Those are questions for your local masjid or a scholar.

What goes in

The latitude and longitude of your place, the calendar date there (in the place’s own time zone), and two settings: the calculation method and the ʿAṣr time. The calculation asks nothing of any server. Without an account, your place is not sent to us. If you sign in, a copy of your settings is kept on Sabīl’s server so that your other devices can have it, and the place you chose goes with it, its latitude and longitude rounded to two decimal places of a degree (about one kilometre). It is not sent to anyone else.

What each time is tied to

• Fajr: before sunrise, the moment the sun is a set angle below the horizon. The angle comes from the method.
• Sunrise and sunset: the moment the sun stands five sixths of a degree below the horizon. Maghrib is sunset, with any minutes the method adds; the Tehran method, below, is the exception.
• Ẓuhr: midday. On this page midday means the sun’s transit, which the package’s code describes as the time the sun is at its highest point in the sky. Any minutes the method adds are added to it.
• ʿAṣr: after midday, the moment an upright object’s shadow has grown to its midday length plus a set multiple of the object’s height. The package works the midday length out from the place’s latitude and the sun’s declination (how far north or south of the equator the sun stands) on that date.
• ʿIshā’: after sunset, the moment the sun is the method’s angle below the horizon; in two methods, a fixed number of minutes after sunset.

What a calculation method is

In the code a method is a name with a few numbers: a Fajr angle, and either an ʿIshā’ angle or an interval after sunset. Some also carry minutes added to particular times. Most carry the name of an institution; Dubai, Kuwait, Qatar and Singapore carry the name of a place. Sabīl offers twelve, with the values the adhan package gives each:

• Muslim World League: Fajr 18°, ʿIshā’ 17°.
• Egyptian General Authority of Survey: Fajr 19.5°, ʿIshā’ 17.5°.
• University of Islamic Sciences, Karachi: Fajr 18°, ʿIshā’ 18°.
• Umm al-Qurā, Makkah: Fajr 18.5°, ʿIshā’ 90 minutes after sunset.
• Dubai: Fajr 18.2°, ʿIshā’ 18.2°. Sunrise three minutes earlier; Ẓuhr, ʿAṣr and Maghrib three minutes later.
• Kuwait: Fajr 18°, ʿIshā’ 17.5°.
• Qatar: Fajr 18°, ʿIshā’ 90 minutes after sunset.
• Singapore · Southeast Asia: Fajr 20°, ʿIshā’ 18°.
• Diyanet, Türkiye: Fajr 18°, ʿIshā’ 17°. Sunrise seven minutes earlier; Ẓuhr five, ʿAṣr four and Maghrib seven minutes later. The package calls this an approximation of the Diyanet method.
• Institute of Geophysics, Tehran: Fajr 17.7°, ʿIshā’ 14°. Maghrib is the moment the sun is 4.5° below the horizon, where that falls after sunset and before ʿIshā’; otherwise it is sunset.
• ISNA, North America: Fajr 15°, ʿIshā’ 15°.
• Moonsighting Committee: Fajr 18°, ʿIshā’ 18°. Five minutes added to Ẓuhr and three to Maghrib.

The Muslim World League, Egyptian, Karachi, Singapore and ISNA methods each add one minute to Ẓuhr.

The package’s guide to its methods carries a note on Umm al-Qurā: that an adjustment of thirty minutes should be added to ʿIshā’ during Ramaḍān. Sabīl’s code sets no such adjustment, so under this method its ʿIshā’ is ninety minutes after sunset in Ramaḍān as in every other month. This page reports both facts and does not say which is right.

The two ʿAṣr settings

The setting named “Standard · Shāfiʿī, Mālikī, Ḥanbalī” uses a multiple of one: the shadow is its midday length plus the object’s own height. The setting named “Later · Ḥanafī” uses two: the midday length plus twice the height. Those names are the app’s. The package calls the two Shafi and Hanafi, and describes them as the earlier and the later ʿAṣr time.

Limits on Fajr and ʿIshā’

The code’s own note gives the reason for these: far from the equator, twilight may never end in summer. So the package holds Fajr no earlier than a part of the night before sunrise, and ʿIshā’ no later than the same part after sunset; the night is counted from sunset to the next sunrise. Sabīl takes the rule the package recommends for the place: a seventh of the night where the latitude is more than 48° north, and half of it everywhere else. The package compares the latitude as a signed number, so a place at exactly 48° north, and every place south of the equator however far south, gets half the night.

Two exceptions: an ʿIshā’ set by an interval is not limited, and the Moonsighting Committee method has limits of its own, which change with latitude and season. At a latitude of 55° north or more, that method takes a seventh of the night instead of the angle, before sunrise for Fajr and after sunset for ʿIshā’; its own limits then apply as they do elsewhere.

The package also has an option for places where the sun does not rise or set at all. Sabīl’s code does not turn it on, and without it the package gives no value for the times it cannot compute.

Minutes and rounding

Once a method’s minutes are added, each time is rounded to the nearest minute; “Singapore · Southeast Asia” rounds up to the next minute instead. Sabīl has no setting for adding minutes of your own, and it adds no margin: on the Ramaḍān page, “Suḥūr ends” is the start of Fajr and “Ifṭār” the start of Maghrib, as calculated.

The method you start with

Until you choose, both settings are on “Follow my region”, which goes by the country of your place. For a city picked from Sabīl’s list that is the city’s country; for a place set from the phone’s location or from typed coordinates, it is the country of the nearest city in that list.

• Bangladesh, Pakistan, India, Afghanistan, Nepal, Sri Lanka, the Maldives: University of Islamic Sciences, Karachi.
• Saudi Arabia, Yemen: Umm al-Qurā, Makkah.
• The United Arab Emirates, Oman: Dubai.
• Kuwait: Kuwait. Qatar, Bahrain: Qatar.
• Egypt, Sudan, Libya, Syria, Lebanon, Iraq, Jordan, Palestine: Egyptian General Authority of Survey.
• Türkiye: Diyanet. Iran: Institute of Geophysics, Tehran.
• Indonesia, Malaysia, Singapore, Brunei: Singapore · Southeast Asia.
• The United States, Canada: ISNA, North America.
• The United Kingdom, Ireland: Moonsighting Committee.
• Everywhere else: Muslim World League.

ʿAṣr starts on “Later · Ḥanafī” in Bangladesh, Pakistan, India, Afghanistan, Nepal, Türkiye, Uzbekistan, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Azerbaijan, Bosnia and Herzegovina, Albania, Kosovo and North Macedonia, and on “Standard” elsewhere. The app calls these regional defaults provisional until its Shariah board confirms them. You can choose your own in Settings at any time.

Why a masjid’s timetable may differ

A masjid or an authority may use another method, or a timetable of its own. The methods above already differ from one another: in their angles, in the minutes they add and, in one case, in how they round. Sabīl also calculates for a single point: a city picked from its list is the city’s centre, to about a kilometre. Which timetable to follow is for your masjid or a scholar to say.

Where to go next

• Salah shows today’s times and names the method in use.
• Prayer times by city has today’s times and this month’s timetable for each city of the app’s list, worked out with the method the app defaults to there.
• The prayer timetable gives a month for any place, to print.
• The Hijri calendar: in the app, the Hijri day moves on at the Maghrib calculated here.
• The qibla is worked out on the phone too.