Why Prayer Times Differ Between Apps and Mosques

Blog · Prayer and Ramadan · 8 min read · Published 31 August 2026 · Updated 5 September 2026

Two apps can show different prayer times for the same street on the same day, and both can be calculated correctly. The differences come from settings, not from mistakes. Fajr and isha depend on a twilight angle that each method chooses differently. Asr depends on a shadow-length convention, and there are two of them in common use, which on a normal day puts the two answers roughly an hour apart. A few methods replace the isha angle with a fixed number of minutes. Near the poles, the geometry stops working entirely and a substitute rule takes over. On top of all of that, a printed mosque timetable is usually rounded, and often carries a few extra minutes on purpose.

None of that makes one app wrong and another right. It means they are answering slightly different questions. This page explains which question each setting asks.

Key facts

• Sunrise, dhuhr, maghrib and sunset come from solar geometry and vary little between calculators. Fajr, asr and isha are where the differences live.
• Fajr and isha are defined by how far the sun sits below the horizon. Published methods use angles from 12 to 20 degrees.
• The two asr conventions (shadow equal to the object’s length, or twice its length) were 57 minutes apart in Istanbul and 69 minutes apart in Kuala Lumpur on 31 August 2026, using Muslim World League angles.
• Umm al-Qura does not use an isha angle at all. It uses a fixed interval of 90 minutes after maghrib.
• Above roughly 48.5 degrees latitude, an 18 degree fajr has no solution around midsummer. Three named substitute rules exist, and they disagree by more than an hour.
• Mosque timetables are usually rounded to the minute or the five minutes, and may add a small safety margin.
• For fasting and for congregational prayer, follow your local mosque or national religious authority. This page describes methods; it does not issue rulings.

The twilight angle is the biggest single cause

Fajr begins when the sky starts to lighten before sunrise, and isha begins when the evening light has gone. Both are visual events, so a calculator has to translate them into something it can compute: how many degrees the sun sits below the horizon. That number is the method’s defining parameter.

These are the published parameters for the most widely used methods, verified on 31 August 2026 against the AlAdhan methods endpoint.

That endpoint lists its Turkey entry as experimental, so treat the Diyanet row as the parameters a calculator applies rather than as an official publication by Diyanet itself. The spread is wide, and it does not stay constant. Because the sun approaches the horizon at a shallower angle away from the equator, the same two methods that sit close together in a tropical city in March can be far apart in a northern city in June.

That is also why our city pages are not all set to the same method. Istanbul defaults to Diyanet, Makkah to Umm al-Qura, and Kuala Lumpur to JAKIM, because that is what the local authority in each place publishes.

Asr follows a shadow, and there are two conventions

Asr is not defined by an angle below the horizon. It is defined by shadow length: the time when an object’s shadow has grown by a set amount past its shortest length at midday.

Two conventions are in common use. In one, asr begins when the shadow equals the object’s own length. In the other, it begins when the shadow equals twice the object’s length. The second is later, always.

The gap is larger than most people expect. On 31 August 2026, holding everything else constant and using Muslim World League angles, the two conventions gave asr at 16:47 and 17:44 in Istanbul, a difference of 57 minutes, and 16:23 and 17:32 in Kuala Lumpur, a difference of 69 minutes. The gap narrows and widens with season and latitude, and a range of roughly 40 to 70 minutes covers most inhabited places for most of the year.

If your app and your mosque disagree by close to an hour on asr alone, while fajr and isha are close, this setting is almost certainly the reason. It is usually labelled by school in the app’s settings.

Some methods use minutes instead of an angle

Umm al-Qura sets isha at 90 minutes after maghrib rather than at an angle. Several Gulf authorities use the same approach with their own intervals.

These parameters are not permanent, which is the part almost nobody mentions. PrayTimes records that the Umm al-Qura fajr angle was 19 degrees before Muharram 1430, that is December 2008, and 18.5 after it. An old app, or an old printed table, can be internally consistent and still disagree with a current one for that reason alone.

A fixed interval has a practical advantage: it never fails. An angle-based isha can become impossible to compute in high summer, but 90 minutes after maghrib always lands somewhere. The trade-off is that a fixed interval and an angle drift apart across the year, since real twilight lengthens and shortens with the season while the interval does not.

Above about 48 degrees, the geometry runs out

The Earth’s tilt is 23.44 degrees, so past about 48.5 degrees of latitude the midsummer sun never reaches 18 degrees below the horizon. In a northern European summer, an 18 degree fajr simply has no solution. Calculators fall back to one of three named substitute rules: middle of the night, one seventh of the night, or an angle-based proportion.

They do not agree. For Reykjavik on 15 June 2026, using Muslim World League angles, the three rules give fajr at 01:29, 02:32 and 02:04, and isha at 01:28, 00:25 and 00:50. That is a spread of more than an hour on fajr, produced entirely by which fallback the app happens to prefer.

So apps disagree most in the places with the longest summer days, which is why northern communities usually publish one agreed timetable rather than leaving it to software.

Mosque timetables are not raw output

A printed timetable is a human document. It is usually rounded, often to five minutes. Many mosques add a small margin to fajr so that nobody is caught short by rounding or by a watch that runs fast. Some print a single time for a whole city, ignoring the few minutes that separate one end of it from the other.

None of that is an error. It is a timetable built for people walking to a building, not raw output from an ephemeris.

What to do with the difference

Match your app’s method and asr convention to the mosque you actually pray in, then stop comparing. If you want to see the parameter set your app is using, AlAdhan’s own methods page lists Umm Al-Qura University, Makkah among them alongside every other method named above, and it is the same table the endpoint serves. A single consistent source is more useful than the average of four. Our prayer times pages show the method used for each city, so you can see which parameters produced the numbers, and the Hijri calendar covers the separate question of which date it is.

For anything that depends on the timing being right for you, and especially for fasting, follow your local mosque or national religious authority rather than any app, this one included. The Quran Habit app carries no prayer times and no qibla: the timetables here are a website feature, and the app is for reading the Quran and keeping a daily habit.

Differences between calculators are conventions, openly published and easy to check. They are not errors, and knowing which one you are looking at removes most of the confusion.