How prayer times are calculated

Two things decide the answer on the home page: your five daily prayer times, and the restricted times in which prayer is withheld. This page explains, in plain language, where those times come from, why different authorities publish slightly different Fajr and Isha, and which authority and method applies in your country. Everything is worked out on your own device: no prayer-times service is ever contacted, and your location never leaves your phone.

The one thing authorities differ on: twilight

Sunrise, midday (the sun's highest point), and sunset are simple astronomy. Every authority in the world agrees on them to the minute, and they are what decide the “can I pray now” answer. There is nothing to disagree about.

The two prayers that are defined by a judgement call are Fajr (dawn) and Isha (night), because the sky brightens and darkens gradually - there is no single sharp instant when “dawn” begins or night “fully” falls. Authorities pin it down by measuring how far the sun has sunk below the horizon.

After sunset the sun keeps travelling downward - you simply cannot see it any more. When astronomers say “Isha begins at 17 degrees”, they mean: the moment the centre of the sun is 17 degrees below the horizon, the evening glow is gone and night has begun. For Fajr, “18 degrees” means the sun has climbed back to 18 degrees below the horizon before sunrise, and the first thread of dawn light appears. A bigger angle means a darker sky, which makes Fajr earlier and Isha later.

So “Fajr 18°, Isha 17°” is one authority's precise definition of dawn and nightfall. Another authority might use 15°, or 20°, because its scholars judged that first-light or full-dark moment slightly differently for their part of the world. It is like two photographers disagreeing on the exact minute “dawn” starts: the sun's angle below the horizon is just the ruler everyone uses to settle it.

Terms, in plain language

Your local authority is the default

Wherever you are, the app starts from your country's own recognised prayer-time authority, because they know their country best and their times are what your local mosque prays by. This works in one of two ways:

• Where we have the authority's own published timetable (Sri Lanka's ACJU and Malaysia's JAKIM today), the app serves those exact printed times, matched to your nearest district zone.
• Everywhere else, the app computes the times using the very method that authority uses. This is not a fallback to something generic: most national authorities define their official times by a calculation method (Saudi Arabia by Umm al-Qura, Egypt by the Egyptian Survey, North America by ISNA), so computing with that method reproduces the authority's own times.

You are never locked in. In Settings → Calculation method you can switch to any other method and watch the times change, and switch back to your authority whenever you like. Nothing is fetched from the internet to do this; the whole calculation runs on your device.

The calculation methods

Angles are how far below the horizon the sun sits when each prayer begins; a few authorities define Isha as a fixed number of minutes after Maghrib instead. Sri Lanka's ACJU and Indonesia's Kemenag are fitted to those authorities' own published tables; the rest are standard published conventions.

No method involves an internet call. Each is a small table of angles applied to the sun's position for your coordinates and today's date, entirely on your device. For the exact parameters behind each one - the fixed-interval and Shia conventions, the Asr rule, high latitudes, and a side-by-side difference table - see calculation methods in depth.

Every country: its authority and the method it uses

This is the reference the app's defaults are built from. “Served by” is either the authority's own extracted timetable (their printed numbers), or computed with the authority's own method. A handful of authorities publish tables that deviate slightly from a pure method (a safety margin, an observational tweak); those are the ones we extract over time - see the last section. Sources are the authorities' own pages.

Middle East, Gulf, North Africa

South, Southeast & Central Asia

Europe, Americas, Africa, Oceania

What we extract vs what we compute

Most national authorities define their official times by a calculation method, so computing with that method is using the local authority - exactly, not approximately. Only a minority publish tables that deviate from a pure method (a safety margin, an observational adjustment, a high-latitude rule). For those, we extract the authority's real numbers into a baked table, one authority at a time, the way Sri Lanka's ACJU is done today. Extraction is an offline, once-a-year step; the app itself never calls a prayer-times service.

Extracted so far: Sri Lanka (ACJU) and Malaysia (JAKIM, 60 official zones). Queued next, in rough order: Indonesia (Kemenag), Turkey (Diyanet), Bangladesh (Islamic Foundation), the Balkan takvim authorities, the UK and Nordic high-latitude timetables, Morocco (Habous), and the Central Asian boards. Until each is extracted, its country is served by computing with that authority's own method, which is already correct for the great majority.

Sources for the tables above are the authorities' own publications; the full evidence, per country, is maintained in the project's research record. Times you see on the app are computed astronomically on your device or read from a baked authority table - never fetched live. See the methodology and data sources.