How prayer times are calculated

Everything on this page is computed on your iPhone by the open-source adhan-swift library, from your coordinates, the date and the settings you choose. No times are downloaded from a server.

Calculation methods

Fajr begins when the sun is a set angle below the horizon before sunrise; Isha when it is a set angle below the horizon after sunset. The methods differ in those angles.

Default method by region

The app suggests a method from the country of your location: United States, Canada and Mexico → ISNA; Saudi Arabia, the United Arab Emirates, Qatar, Kuwait, Bahrain, Oman and Yemen → Umm al-Qura; Egypt, Libya, Algeria, Tunisia, Morocco, Sudan, Lebanon, Syria, Jordan, Iraq and Palestine → Egyptian General Authority; Pakistan, India, Bangladesh and Afghanistan → Karachi. Elsewhere, locations in the Americas get ISNA and the rest of the world Muslim World League. The suggestion is only a starting point; you can pick any method.

Asr

Shafiʿi rule: Asr begins when an object's shadow equals its own length (plus the shadow it had at noon). Hanafi rule: when the shadow is twice the object's length. The Shafiʿi rule is also the one used by the Maliki and Hanbali schools; the app offers the two as a setting and takes no position on them.

High latitudes

In summer at high latitudes the sun may never reach the Fajr or Isha angle, so the astronomical time does not exist. The selected rule then sets Fajr and Isha instead:

• Angle-based — the night is divided in proportion to the twilight angle (angle ÷ 60 of the night).
• Middle of the night — Fajr is no earlier, and Isha no later, than the middle of the night.
• One-seventh of the night — Fajr is no earlier than the last seventh of the night, and Isha no later than the first seventh.

Adjustments

Each prayer can be shifted by up to ±30 minutes to match a local timetable. Times are shown in the 12-hour or 24-hour format, in the time zone of the chosen location.

Prayer windows

The app treats each prayer's time as a window: Fajr until sunrise, Dhuhr until Asr, Asr until Maghrib, Maghrib until Isha, Isha until the next Fajr. The current prayer's screen shows how much of its window is left, "before the window ends" reminders count down to it, and the qada counter uses these windows to decide whether a prayer was missed.

Qibla

The qibla is the initial bearing of the great circle from your position to the Kaaba (21.4225° N, 39.8262° E). The compass reads the phone's magnetometer and motion sensors, so it works with the phone flat or held upright. True north is obtained by applying the magnetic declination that iOS reports for your location. Without location access the needle points at magnetic north, and the app says so.

Hijri date

The app uses the Umm al-Qura tabular calendar as implemented by iOS. Because Islamic months are announced by sighting the moon, the tabular date can differ from the date announced where you live; you can shift it by up to ±2 days.

Limitations

• Daylight-saving transitions. Around a clock change, check the times against your local timetable.
• Location accuracy. A few kilometres rarely matter; a wrong city does. Check the location shown in Settings.
• High latitudes. The rules above are conventions; follow your local mosque.
• Compass interference. Magnets, metal, magnetic cases and car mounts deflect the needle; calibrate when asked.
• Device clock and time zone. The app trusts the phone's clock and the time zone of the chosen location.

Not a ruling