Why do different prayer apps show different times for the same city?

Because prayer times are not read from a fixed table - they are calculated from the sun's angle below the horizon at your exact coordinates, and different Islamic authorities have historically set slightly different angle thresholds for Fajr and Isha. Two apps using different calculation methods can legitimately show times a few minutes apart for the same location.

Which calculation method should I use?

Whichever method matches your local mosque, so your prayer app and your community stay in sync. If you are unsure, Muslim World League is a widely used global default; North American users often use ISNA; users in Saudi Arabia typically use Umm al-Qura; Egypt and much of Africa commonly use the Egyptian General Authority method.

What is the difference between Hanafi and Shafi'i Asr timing?

The two schools differ on when a shadow is long enough to mark the start of Asr. The Shafi'i (and Maliki, Hanbali) view uses the point where an object's shadow equals its own height; the Hanafi view uses double that shadow length, which makes Hanafi Asr fall noticeably later in the afternoon. Set whichever matches your school of thought or local mosque.

Prayer Time Calculation Methods Explained: Which One Should You Use?

Prayer times aren't looked up from a fixed table anywhere. They're calculated, fresh, from your exact coordinates, the date, and the sun's angle below the horizon - Fajr begins at true dawn, Isha at the disappearance of twilight, both defined by that solar angle rather than a clock time. The catch is that different Islamic scholarly bodies, over the decades, have set slightly different angle thresholds for exactly when "dawn" and "twilight" count as having started. None of them are wrong - they're different, careful conclusions reached by different authorities, and the differences usually amount to a handful of minutes.

The main methods, and who typically uses them

Muslim World League (MWL) - Fajr 18°, Isha 17°. Probably the most widely used global default, and a safe starting point if you're unsure.
Islamic Society of North America (ISNA) - Fajr 15°, Isha 15°. Common across the US and Canada.
Umm al-Qura, Makkah - Fajr 18.5°, Isha a fixed 90 minutes after Maghrib. Standard across Saudi Arabia.
Egyptian General Authority of Survey - Fajr 19.5°, Isha 17.5°. Common across Egypt and parts of Africa.
University of Islamic Sciences, Karachi - Fajr 18°, Isha 18°. Widely used across South Asia.
Dubai / Gulf variants - regional adjustments used by several Gulf authorities.

None of these is "the correct one" in some universal sense - pick the one your local mosque follows, and your app and your community will agree.

Asr: the other place apps disagree

Separately from the method above, there's a second variable specific to Asr: the Hanafi school defines Asr as starting when an object's shadow is twice its height (plus the shadow length at noon), while the Shafi'i, Maliki and Hanbali schools use one times its height. In practice this means Hanafi Asr falls noticeably later in the afternoon than Shafi'i Asr - sometimes 30-60 minutes, depending on latitude and season. If your Asr time looks "wrong," this setting, not the calculation method, is almost always the reason.

"Indeed, prayer has been decreed upon the believers a decree of specified times." - Surah An-Nisa, 4:103

How to get it right in HayatTime

Open Settings and find the prayer calculation method.
Match it to your local mosque - if you don't know, ask, or start with Muslim World League as a sensible default.
Set your Asr school (Hanafi or Shafi'i) to match your own practice or your mosque's.
If your mosque's times still differ by a couple of minutes from the calculation (this is normal - many mosques apply small manual adjustments of their own), use HayatTime's per-prayer minute adjustment to match exactly.

Once set, this feeds directly into HayatTime's Home Screen and Lock Screen widgets, your Fajr alarm, and salah blocking windows - set it once, and everything downstream follows automatically.

Try it

Get your calculation method right once, and HayatTime keeps every prayer-time feature - widgets, alarm, and blocking - accurate without you thinking about it again.