Building a prayer times and qibla app: calculation methods, notifications and accuracy

How prayer times are calculated

Prayer times are calculated from the position of the sun relative to the user's location on a given date. Each prayer is tied to a solar event, and standard astronomical formulas give the sun's position for any date, latitude and longitude:

• Fajr begins at true dawn, defined in calculation as the moment the sun reaches a set angle below the horizon before sunrise.
• Sunrise is shown because it marks the end of Fajr time, even though it is not a prayer.
• Dhuhr begins just after solar noon, when the sun passes its highest point.
• Asr is defined by the length of an object's shadow, discussed below.
• Maghrib begins at sunset.
• Isha begins when evening twilight disappears, defined either by an angle below the horizon or, in some methods, by a fixed interval after Maghrib.

The inputs are latitude, longitude, the date and the time zone, including any daylight saving rules where they apply. Some apps also consider elevation for sunrise and sunset. Because everything comes from formulas, the whole calculation can run on the phone with no server and no connection, which is the right design for an app people rely on several times a day.

Why calculation methods differ, and which one to use

Calculation methods differ because authorities define dawn and nightfall differently. The main variable is the angle of the sun below the horizon used for Fajr and Isha; a few methods use a fixed interval after Maghrib for Isha instead. A small difference in angle can move Fajr by several minutes, more at higher latitudes.

The practical rule is simple: default to the method used by the local authority and the local mosques, detected from the user's country, and say which method is in use on the main screen. During testing, compare the app's output against the official published timetable for several cities and seasons. If the numbers disagree by more than a minute or two, check the method, the time zone, the rounding and any precautionary minutes the authority adds to its published times.

Asr settings and high-latitude adjustments

Asr has two widely used settings, reflecting a difference between the schools of jurisprudence. In the majority view, held by the Shafi'i, Maliki and Hanbali schools, Asr begins when an object's shadow equals its length plus the shadow it had at noon. In the Hanafi view, it begins when the shadow reaches twice the object's length plus the noon shadow, which gives a later time. The app should default to the setting common in the user's country and offer the other clearly labelled.

High latitudes need special handling. In summer, far from the equator, the sun may not go deep enough below the horizon for the twilight angle ever to be reached, so a pure angle-based calculation produces no Fajr or Isha time at all, or an unrealistic one. Libraries and authorities use adjustment rules for this, commonly known as middle of the night, one-seventh of the night, and angle-based (twilight angle as a proportion of the night).

For an app focused on Saudi Arabia and the Gulf, these rules rarely change anything at home. They matter for users who travel or study abroad, which is common. Choose a default rule with the scholars who review the app, document it in the settings, and test cities in northern Europe in June as part of the test suite.

Settings, offsets and location privacy

Give users control without making them configure anything on day one. The settings screen of a well-built prayer times app usually offers:

• Calculation method, pre-selected from the user's country.
• Asr setting: majority or Hanafi.
• High-latitude rule, shown only when relevant.
• Manual offsets in minutes per prayer, so a user can match their local mosque's timetable exactly.
• Location mode: automatic, or a city chosen manually for users who prefer not to share location.
• Hijri date adjustment of a day forward or back.

Location is personal data, so ask for the least you need. Permission "while using the app" is enough to calculate times; the coordinates can stay on the device, and the app only needs to recalculate when the user moves to another city. Explain the request in plain words before the system prompt appears. Disclose location use honestly in the Apple App Store privacy details and the Google Play data safety section, and keep in mind that personal data in Saudi Arabia falls under the Personal Data Protection Law (PDPL); confirm specifics with qualified counsel.

Remember the difference between the adhan time and the iqama. Mosques set their own iqama times, so an app that serves a mosque community may add a mosque-managed iqama schedule alongside the calculated times rather than mixing the two.

Reliable adhan notifications on iOS and Android

Reliable notifications come from scheduling them in advance on the device, because neither iOS nor Android lets an app run freely in the background to check the time. This is where most prayer apps earn or lose their reviews.

1. Schedule ahead as local notifications. Calculate the coming days and register each prayer as a scheduled notification. They fire offline and survive the app being closed.
2. Refresh the window. iOS caps how many local notifications an app may have pending, so schedule a rolling window and top it up whenever the app opens or gets background time.
3. Respect sound limits. iOS plays only a short custom sound for a notification, so a full adhan cannot be the notification sound; use a short adhan excerpt, and play the full adhan only if the user opens the app.
4. Handle Android's restrictions. Recent Android versions restrict exact alarms behind a permission, and Google Play policy limits which apps may declare the related permissions, so check the current rules. Some manufacturers' battery optimisation delays or cancels background work. Request what is needed, explain why, and guide users to exclude the app from battery optimisation where it helps.
5. Re-schedule after changes. A new method, offset, time zone, reboot or location change must rebuild the schedule.
6. Test on real devices. Emulators do not reproduce manufacturer battery behaviour. Test across several brands and OS versions before release.

Keep notification options humane: per-prayer on and off, adhan or silent alert, a reminder some minutes before, and respect for the phone's silent and focus modes. A pre-Fajr alert is helpful for some users and unwelcome for others, so make it opt-in.

How qibla direction and Hijri dates work

The qibla direction is the initial bearing of the great-circle route from the user's location to the Kaaba in Makkah, the shortest path over the surface of the Earth. It is calculated with standard spherical trigonometry from the two sets of coordinates. A straight line on a flat map gives a different and wrong answer for distant locations, which is a classic bug.

The compass is the harder part. A phone's magnetometer measures magnetic north, which differs from true north by the local magnetic declination; both iOS and Android provide ways to obtain a true heading or the declination for a location. The sensor is also disturbed by metal, magnets in phone cases and nearby electronics. A good qibla screen asks the user to calibrate when accuracy is low, shows the accuracy honestly, and offers a map view that draws the great-circle path towards Makkah, so the user can line it up with streets or buildings without relying on the compass.

Hijri dates need humility. The Umm al-Qura calendar is the official Hijri calendar in Saudi Arabia and can be calculated in advance. But the start of months tied to worship, such as Ramadan, Shawwal and Dhu al-Hijjah, is confirmed by moon sighting and announced officially, and may differ from the calculated date by a day. Show the calculated date as expected, let users adjust by a day, and if the app has a server, push an official correction when an announcement is made.

Planning a prayer times app, and how it connects to Quran features

A prayer times app is a precision tool, so the first release should be narrow and exact: correct times with a visible method, reliable notifications, a qibla screen with honest accuracy, the Hijri date, offline operation and a calm Arabic-first interface. Everything else can wait until users trust the times.

Many organisations then want to grow it into a fuller daily companion: adhkar linked to prayer times, as described in what a good adhkar app needs, a Quran reader, and gentle reading goals, as covered in designing Quran habit features. For the reader itself, see what a Quran app needs.

Aalim, the Quran learning app FLUIDS designed and built, does not include prayer times or qibla. What carries over are its foundations: a calm reader in authentic Uthmani script, surahs available offline, Arabic-first design, and reading kept separate from AI features that need a connection. Those are the same foundations a combined prayer and Quran app needs.

FLUIDS builds mobile apps and custom software for organisations and founders in Saudi Arabia and the GCC, and the client owns the source code. Start with the mobile app MVP guide or the Aalim case study; scope, price and timeline are agreed in a written proposal before development.