How are Islamic prayer times calculated?

Prayer times move a little every day, and they are different in every town. That's because each prayer is tied to the sun, not the clock.

Fajr begins at first light, Dhuhr just after midday, Asr when shadows have grown, Maghrib at sunset and Isha once the sky is dark. A timetable simply works out when those moments happen where you live.

Dawn and dusk work a little differently. Light comes and goes gradually rather than at one exact moment, so Islamic organisations have each defined when Fajr and Isha begin. That's why two timetables for the same town can differ by several minutes, and in the UK by much more in summer.

To find today's times where you are: use your local mosque's timetable, or a prayer times app such as Pillars, which works them out from your location.

What decides each prayer time?

Every prayer time is a moment in the sun's journey across the sky. To turn that moment into a clock time, a timetable needs only three things: where you are, the date and your time zone.

Fajr

Begins at first light. True dawn is a band of light spreading along the horizon. Scholars distinguish it from false dawn, a faint upright glow that comes earlier and then fades. A hadith in Sahih Muslim says not to be misled by "this whiteness… until it spreads". Fajr ends at sunrise.

Dhuhr

Begins just after midday. That is the moment the sun passes its highest point, called solar noon. It is rarely 12:00 on the clock: it shifts with where you are in your time zone and with the time of year. Many timetables add a few minutes as a safety margin.

Asr

Begins when shadows have grown. In most schools, the time of Asr enters when an object's shadow is as long as the object itself, plus the short shadow it had at noon. The Hanafi school, in the position of Imam Abu Hanifa, holds that it enters when the shadow is twice as long, so Hanafi Asr comes later. Both views come from the same hadith, in which Jibril led the prayers on two days (Jami' at-Tirmidhi 149).

Maghrib

Begins at sunset, as soon as the sun has fully set.

Isha

Begins when the sky is dark, once the last glow of dusk (the shafaq) has gone from the western sky. Schools differ on which glow counts: the red glow, or the white glow that lingers after it.

Sunrise, noon and sunset can be calculated to the minute. Dawn and dusk build and fade over an hour or more, so every timetable needs an agreed definition of when dawn has begun and when night has fallen. That definition is called a calculation method.

Why are there different calculation methods?

There is no exact starting line for dawn or dusk. Astronomers track twilight by how far the sun is below the horizon, measured in degrees:

• 6° below: the sky is getting dim.
• 12° below: the horizon is hard to see.
• 18° below: the sky is fully dark.

HM Nautical Almanac Office (HMNAO), which publishes the UK's official sunrise and sunset data, says there is "no general agreement on a precise definition of 'dawn'".

Each calculation method picks its angles: one for dawn (Fajr), one for nightfall (Isha), and sometimes a few extra rules. Islamic organisations around the world have each made their own choice, so different regions tend to follow different methods:

Angles and regions from praytimes.org; Moonsighting Committee from moonsighting.com.

A few of these are worth knowing:

• Muslim World League
  One of the most widely used methods outside North America. Dawn is at 18° and nightfall at 17°.
• ISNA
  Uses a smaller angle of 15° for both, so Fajr comes later and Isha earlier than with most methods.
• Umm al-Qura
  The method used in Saudi Arabia. Isha begins a fixed 90 minutes after sunset (120 in Ramadan) rather than at an angle.
• Moonsighting Committee
  Built by Khalid Shaukat from years of sky observations. Its dawn and nightfall angles change with the season and with how far north you are, rather than staying fixed.

Why are UK prayer times so different in summer?

In summer, the UK's nights are too short and too bright for some of these angles to happen at all. The further north you are, the less the sun dips below the horizon on a summer night. HMNAO notes that in June and July the sun "does not reach 18° in many parts of the British Isles", and in the north of Scotland it doesn't even reach 12°.

So for weeks around midsummer the sky never gets fully dark. In London that lasts about two months, from late May to late July. If dawn never technically arrives, there is no moment to calculate Fajr from. Timetables fill the gap with a high-latitude rule, which shares out the night instead:

• Middle of the night: Fajr no earlier than halfway between sunset and sunrise.
• One-seventh of the night: split the night into seven parts; Fajr no earlier than the start of the last part.
• Twilight angle: a share of the night based on the method's angle, so an 18° method uses 18/60 of it.

In June, the choice of rule matters more than the method. With the same method, in the same place, on the same night, Fajr moves by 2 hours 38 minutes depending on the rule:

How do UK mosques decide their times?

There is no single UK method. Each mosque or scholarly body chooses its own model, and several explain theirs publicly:

• London Unified Prayer Timetable (LUPT) was adopted from 1 August 2011 by a group of London mosques, including the London Central Mosque, East London Mosque, Mayfair Islamic Centre and Muslim Welfare House. It is based on Khalid Shaukat's moonsighting.com model, which uses observation data "including observations made by Hizbul Ulama in the north of England". It is voluntary and meant for inside the M25.
• East London Mosque takes sunrise from HMNAO and subtracts 3 minutes, and adds 5 minutes to Dhuhr and 3 to Maghrib "to allow coverage of the whole M25 region". It publishes both Asr times, "Mithl 1" and "Mithl 2" (one and two shadow lengths).
• Hizbul Ulama (Blackburn) bases its UK town tables for Fajr and Isha on naked-eye observations made in Blackburn from September 1987 to August 1988.
• Wifaqul Ulama (Britain) uses 18° for Fajr. In persistent twilight it uses either the last day 18° occurred or half the night, "not both".
• Islamic Centre Edgware uses HMNAO data at about 17.5°, and disagrees with extending modified times beyond the persistent-twilight months.
• HNCO (Nelson) uses one-seventh for Scotland and Northern Ireland from April to September, and twilight angles elsewhere.

Example: Fajr in London today. The city's unified timetable next to two calculation methods:

For the full month, with jama'ah times for London mosques, see London prayer times.

How much do the methods differ?

On an ordinary day in London, the six common methods put Fajr up to about 50 minutes apart and Isha about 40 minutes apart. Around midsummer the gaps grow to well over an hour for Fajr and over two hours for Isha.

Calculated for central London with six methods (MWL, ISNA, Egypt, Umm al-Qura, Moonsighting Committee and France), with the middle-of-the-night rule in summer.

Try it for your city. Choose a city, or use your location, to see today's Fajr and Isha under each of the six methods:

Calculated for the city centre, with the middle-of-the-night rule in summer.

How do I choose the right method?

Start with your mosque, then match your app to it.

1. Check your local mosque's timetable
   If your mosque publishes one, use it as your reference.
2. Match the method
   Compare a few days of Fajr and Isha with the mosque's until they line up.
3. Match Asr
   Choose standard or Hanafi to match the mosque.
4. Match the high-latitude rule
   This matters most from May to August in the UK.
5. Adjust single prayers
   Add or take away a few minutes to cover the mosque's safety margins.

In Pillars, all of this is in Settings, under Prayer Times:

• Autopilot
  On by default. It picks a valid calculation method for the country you are in, and changes it as you travel (in supported countries).
• Calculation method
  Turn Auto-Detect off to choose your own from 23 methods, each listed with its Fajr and Isha angles.
• Asr time
  Earlier Asr (Shafi'i, Maliki and Hanbali) or later Asr (Hanafi), or show both.
• High-latitude rule
  Twilight angle, middle of the night or one-seventh of the night.
• Custom angles
  Set your own angles for Fajr and Isha.
• Custom adjustments
  Move any time, including sunrise, a few minutes earlier or later to match your mosque.

Keep reading

• When does Fajr start and end?
• When does Isha end?
• What time is Tahajjud?
• Best Muslim prayer apps 2026
• Pillars prayer times app