How Islamic Prayer Times Are Calculated (and Why Apps Disagree)
Prayer times are astronomy, not a fixed timetable. Understanding the sun angles explains why your two favourite apps don't always agree.
Open two prayer-time apps in the same city and you'll often find Fajr a few minutes apart, maybe Isha too. It's a common source of quiet worry — which one is right? The reassuring answer is that both can be correct: prayer times aren't read off a fixed timetable, they're calculated from the position of the sun, and reasonable people have adopted slightly different conventions for the edges. Once you understand what's actually being computed, the small differences stop being alarming and start making sense.
Prayer times are astronomy, not a schedule
Each of the five daily prayers begins at a moment defined by where the sun is in the sky from your exact location. That means the times depend on three things: your latitude and longitude, the date (the sun's path shifts through the year), and the convention used for the twilight prayers. Because the inputs are astronomical, the times shift daily and differ by city — there's no single global clock for them. The salah times calculator computes them for your coordinates and chosen method.
What defines each prayer's time
Three of the five are tied to clearly visible solar events, and two — the dawn and night prayers — are defined by how far the sun sits *below* the horizon, which is where the methods come in:
- Fajr — begins at true dawn, when the first light appears along the horizon. Defined by the sun reaching a set angle below the horizon (commonly around 15°–18°).
- Sunrise — marks the end of the Fajr window; the sun's upper edge appears.
- Dhuhr — begins just after the sun passes its highest point (solar noon) and starts to decline.
- Asr — begins when an object's shadow reaches a defined multiple of its own length (the two main schools differ on whether that's one or two times the object's length plus the noon shadow).
- Maghrib — begins at sunset, when the sun's upper edge dips below the horizon.
- Isha — begins when the evening twilight fully fades, again defined by a set sun angle below the horizon (commonly around 15°–18°).
Asr is why you'll see two times for one prayer
The Hanafi school generally begins Asr later — when a shadow equals twice the object's length plus its noon shadow — while the majority (Shafi'i, Maliki, Hanbali) begin it at one times. That's not an error; it's a genuine difference of fiqh. A good calculator lets you pick, so set it to the school you follow.
Why two apps disagree
Almost every disagreement traces back to the calculation method — the specific sun angles a given authority uses for Fajr and Isha. Different bodies around the world have published slightly different angles based on local observation and scholarship:
- Muslim World League, Umm al-Qura (Makkah), Egyptian General Authority, the University of Islamic Sciences, Karachi, and ISNA (North America) each specify their own Fajr/Isha angles or rules.
- Pick a different authority and Fajr and Isha shift by a few minutes — Dhuhr, Maghrib and sunrise barely move because they're tied to direct solar events, not twilight angles.
So the right question isn't "which app is correct?" but "which method does my local mosque or community follow?" Match your tool's method to that, and your times will line up with the people you pray with. The salah times calculator exposes the method setting precisely so you can match your locale.
The high-latitude problem
Near the poles, the sun never reaches the angle
In far-northern or far-southern places during summer, twilight can persist all night — the sun never dips to the Fajr/Isha angle at all, so a literal calculation produces no valid time. Scholars have approved several adjustment methods (such as using the nearest moderate latitude, or dividing the night into portions). If you live at a high latitude, choose a tool that offers a high-latitude rule and follow your local scholarly guidance on which to use.
Sehri, Iftar, and the same underlying math
Ramadan timetables run on exactly this machinery. Sehri (the pre-dawn meal) must end by the start of Fajr, and Iftar begins at Maghrib (sunset) — so a Ramadan schedule is really just the Fajr and Maghrib columns of the daily calculation, listed for the month. The Sehri & Iftar schedule calculator builds that month-long table from the same coordinates and method, which is why it's important to set the method consistently with your daily prayer times.
A related calculation: the Qibla
While we're on location-based worship, the Qibla — the direction to face for prayer — is a sibling calculation. It's the great-circle bearing from your coordinates to the Kaaba in Makkah, which is why it isn't simply "south" or "east" but a precise compass angle that changes with where you stand. The Qibla direction finder computes that bearing from your position.
None of this diminishes the spiritual weight of the prayers — if anything, knowing that each time is read from the sky, recalculated every single day for the exact spot you're standing on, adds a quiet sense of order to the rhythm. And it means that when two trusted apps differ by three minutes, you can stop worrying and simply follow the method your community prays by.
Tools mentioned in this guide
Put the ideas above to work — every tool is free and runs in your browser.
Frequently asked questions
Why do prayer-time apps show slightly different times?
Because they use different calculation methods — specifically different sun angles below the horizon for Fajr and Isha, published by authorities like the Muslim World League, Umm al-Qura, Karachi, ISNA, and others. Dhuhr, Maghrib, and sunrise barely change since they're tied to direct solar events. Match your tool's method to the one your local mosque follows.
Why are there two different Asr times?
The Hanafi school generally begins Asr later — when an object's shadow equals twice its length plus the noon shadow — while the majority of schools begin it at one times the object's length. Both are valid positions of fiqh, so a good calculator lets you choose the one you follow.
How are Fajr and Isha times determined?
By how far the sun is below the horizon. Fajr begins at true dawn and Isha when evening twilight fully fades, each defined by a set sun angle (commonly around 15°–18°). Different authorities use slightly different angles, which is the main reason apps disagree on these two prayers.
What happens to prayer times near the poles in summer?
At high latitudes the sun may never dip low enough to reach the Fajr or Isha angle, so a literal calculation gives no valid time. Scholars have approved adjustment methods such as using the nearest moderate latitude or dividing the night into portions. Choose a tool with a high-latitude rule and follow local scholarly guidance.
Muhammad Salman Saleem
Full-Stack Web Developer
Guides on Premium Converters are written and maintained by the same person who builds the tools they reference, against the standards on our methodology page. Spotted something that needs correcting? Tell us — fixes are typically published within 48 hours.
Keep reading
How Zakat Is Actually Calculated: Nisab, Hawl, and What Counts
The 2.5% is the easy part. The real questions are what counts, when the clock starts, and which nisab to use — answered here.
Islamic Inheritance (Warasat) Explained: How the Shares Work
Faraiz is one of the most precise systems in Islamic law. Here's how an estate is settled, in order, before any share is worked out.
Marla, Kanal, and How Pakistani Land Measurement Actually Works
Why the same word — Marla — can mean two different sizes a few kilometres apart, and how to check what you are actually buying.