How Prayer Times Are Calculated
The astronomy behind Fajr, Dhuhr, Asr, Maghrib and Isha, and why calculation methods give different times.
It starts with the sun
Every prayer time is tied to the position of the sun at your location. We calculate where the sun is for your latitude, longitude and date, and find the moment it reaches each position. That is why times differ even between nearby cities.
Each prayer, step by step
- Dhuhr: just after solar noon, when the sun is at its highest point.
- Maghrib: sunset, when the top of the sun drops below the horizon (0.833 degrees below, to allow for the atmosphere bending light).
- Fajr and Isha: when the sun is a set angle below the horizon, before dawn and after dusk. This angle is what the calculation methods disagree on.
- Asr: when an object's shadow equals its length plus its noon shadow (Standard), or twice its length plus its noon shadow (Hanafi).
Calculation methods
| Method | Fajr angle | Isha angle | Used in |
|---|---|---|---|
| ISNA | 15° | 15° | North America |
| Muslim World League | 18° | 17° | Europe, Far East |
| Umm al-Qura, Makkah | 18.5° | 90 min after Maghrib | Saudi Arabia |
| Egyptian authority | 19.5° | 17.5° | Africa, Middle East |
| University of Islamic Sciences, Karachi | 18° | 18° | Pakistan, India, Bangladesh |
A bigger angle means an earlier Fajr and a later Isha. Between ISNA and the Egyptian method, Fajr can differ by 20 to 30 minutes.
High latitudes
In summer, far north places such as Scotland or Scandinavia may never get dark enough for the sun to reach 15 or 18 degrees below the horizon. We then limit Fajr and Isha to a share of the night, based on the angle, so the times stay usable.
Why your mosque may differ
Mosques often add a few minutes of safety margin, round to the nearest five minutes, or set a fixed iqamah time. Follow your local mosque when it differs from a calculated time.
Questions
Which prayer time method is most accurate?
All are accurate for what they measure. They differ in which sun angle marks dawn and dusk. Use the one your community follows.
Why is Asr later for Hanafi?
The Hanafi school waits until a shadow is twice an object's length, instead of once, so Asr starts later in the afternoon.
How accurate are calculated times?
Within about a minute of the astronomy. Local terrain and the weather do not change the calculated time.
By the TimeNowTools team · Last reviewed 19 October 2026