How are prayer times calculated? Every prayer is tied to the sun’s position in the sky, and turning that into a clock time for your city is exactly what a prayer times calculator does.
Open two prayer apps side by side and you’ll often see Fajr a few minutes apart, sometimes more. That isn’t a bug — prayer times are worked out from the sun’s position, and there’s more than one accepted way to measure it. Here’s how the whole thing actually works, in plain language.
How are prayer times calculated? The quick answer
The five daily prayers are tied to the position of the sun in the sky, not to a fixed clock. Fajr and Isha depend on how far the sun is below the horizon (twilight), while Dhuhr, Asr and Maghrib depend on the sun’s height and the length of shadows. Because different authorities use slightly different sun angles, the exact minute can vary by location and calculation method.
What each prayer is tied to
Every prayer has a natural sign in the sky. The calculation is really just astronomy translating that sign into a clock time for your exact latitude, longitude and date.
| Prayer | Astronomical event |
|---|---|
| Fajr | True dawn — sun a set angle below the horizon before sunrise |
| Sunrise (Shuruq) | The sun’s upper edge reaches the horizon (end of Fajr) |
| Dhuhr | Just after the sun crosses its highest point (solar noon) |
| Asr | When an object’s shadow reaches a set multiple of its length |
| Maghrib | Sunset — the sun’s disc dips below the horizon |
| Isha | Twilight ends — sun a set angle below the horizon after sunset |
Why Fajr and Isha are the tricky ones
Sunrise, Dhuhr and Maghrib are fairly fixed — the sun either crosses the horizon or the meridian, and there’s little to argue about. Fajr and Isha are different because they mark twilight, which fades gradually. Scholars and astronomers picked specific “depression angles” — how far the sun sits below the horizon — to define the start of dawn and the end of dusk. Common Fajr angles range from about 15° to 19.5°, and Isha from about 15° to 18°. Those few degrees are exactly why apps disagree. We break the angles down in Fajr and Isha angles explained.
The Asr question: one shadow or two
Asr is the other place methods split. In the standard view (Shafi’i, Maliki, Hanbali), Asr begins when an object’s shadow equals its own length, plus the shadow it had at noon. In the Hanafi view, it begins when the shadow reaches twice the object’s length. That’s why Hanafi Asr is noticeably later. Full detail is in Asr time: Hanafi vs Shafi’i.
Calculation methods (why the angles differ)
Different regional authorities standardised their own angles. You’ve probably seen these names in your app’s settings:
- Muslim World League — Fajr 18°, Isha 17°
- ISNA (North America) — Fajr 15°, Isha 15°
- Umm al-Qura (Makkah) — Fajr 18.5°, Isha 90 minutes after Maghrib
- Egyptian Authority — Fajr 19.5°, Isha 17.5°
- Karachi — Fajr 18°, Isha 18°
None is “wrong” — they’re regional conventions. Pick the one your local mosque or community follows. We compare them in prayer calculation methods compared.
What the calculator needs from you
To turn all this into a timetable, a calculator needs three things: your location (latitude and longitude), the date, and your chosen method and Asr school. From there the math is exact. Our prayer times calculator handles it for any city and lets you pick the method and the Hanafi or standard Asr.
A few related timings
Beyond the five prayers, the same sun-based math gives you other useful moments: Zawal (the brief forbidden time at midday), Islamic midnight and the last third of the night, and in Ramadan the Suhoor and Iftar times. And if you’re setting up to pray, you’ll want the Qibla direction for your location.
Frequently asked questions
Why do two apps show different prayer times?
Almost always because they use different calculation methods (Fajr/Isha angles) or a different Asr school. Set both to the same method and they’ll line up.
Are prayer times different every day?
Yes, slightly. As the sun’s path shifts through the year, dawn, noon and sunset move, so each day’s times differ a little from the last.
Which calculation method should I use?
The one your local mosque or national body uses. In North America that’s often ISNA; much of the world uses the Muslim World League; Saudi Arabia uses Umm al-Qura.
Do I need my exact location?
Your city is usually close enough, but exact latitude and longitude give the most accurate minute, especially for Fajr and Maghrib.
The full prayer times guide
Explore each topic in depth:
- When does Fajr begin? Subh Sadiq explained
- Asr time: Hanafi vs Shafi’i
- Prayer calculation methods compared
- Fajr and Isha angles explained
- How long after sunset are Maghrib and Isha?
- Zawal: the forbidden midday time
- Islamic midnight and the last third of the night
- Suhoor and Iftar times in Ramadan
- How to find the Qibla direction
For more background, see Salah times on Wikipedia.
Want a ready timetable for your city? Use the free prayer times calculator — set your location, method and Asr school, and get all five times instantly.