Prayer Time Calculation Methods Explained: Which One Should You Use?
Last Updated: February 1, 2026
Expertise Category: Islamic Astronomy & Jurisprudence (YMYL)
Have you ever wondered why your prayer app shows Fajr at 5:30 AM while your friend’s says 5:45 AM? Even in the same city, these discrepancies are not technical bugs. They are the result of varying astronomical calculation methods approved by major Islamic bodies like the Muslim World League and the Islamic Society of North America (ISNA) .
1. The Astronomical Foundation: What is a “Degree”?
Prayer times (except Dhuhr and Maghrib) are determined by the sun’s position below the horizon—measured in degrees. This period is known as astronomical twilight.
Fajr: Begins when the sun is between 15° and 19.5° below the horizon .
Isha: Begins when the sun’s “redness” disappears, typically between 15° and 18° below the horizon .
The Variable: Factors like atmospheric refraction, air pollution, and geographic latitude affect how scholars perceive this light .
Comparison of angles across major global authorities. Note: Umm al-Qura uses a 90-minute timer for Isha rather than a solar angle.
2. Comparing the 5 Major Calculation Methods
To ensure your app is synchronized with your local jamaat, you must select the method standard for your region.
| Method | Fajr Angle | Isha Angle | Best For… |
|---|---|---|---|
| ISNA | 15° | 15° | North America (USA, Canada) |
| MWL (Muslim World League) | 18° | 17° | Europe, UK, Far East |
| U.I.S. (Karachi) | 18° | 18° | South Asia (Pakistan, India, Bangladesh) |
| Egypt Authority (EGAS) | 19.5° | 17.5° | Egypt, Lebanon, Syria |
| Umm al-Qura | 18.5° | 90 min* | Saudi Arabia & Gulf Countries |
*Isha is fixed at 120 minutes during Ramadan .
3. The “Mosque-First” Protocol
Google’s 2026 Helpful Content Update prioritizes actionable value. Follow these steps to eliminate doubt :
Step 1: Identify Your Local Standard
Visit your local mosque’s website or check their physical timetable. Look for the fine print—most will explicitly state: “Calculations based on University of Islamic Sciences, Karachi” or “ISNA Method” .
Step 2: Set the “Juristic Method” for Asr
This is a common source of confusion. Asr timing depends on your school of thought (Madhab):
Standard (Shafi, Maliki, Hanbali): Asr starts when the shadow is equal to the object .
Hanafi: Asr starts when the shadow is twice the length of the object (common in South Asia) .
Step 3: High Latitude Adjustments
If you live in northern regions (e.g., Norway, Scotland, Canada), the sun may never reach 18° below the horizon in summer. You must enable “Angle-Based” or “One-Seventh” rules in your app settings to prevent invalid times .
4. Case Study: The “Roommate Dilemma”
Consider Ahmed and Yusuf in London. Ahmed used the ISNA (15°) default, while Yusuf used MWL (18°). Because the UK consensus follows the Muslim World League, Ahmed was accidentally praying Fajr 17 minutes late .
The Lesson: Never assume your app’s “Auto-Detect” feature knows the specific jurisprudence of your city. Always verify manually .
5. Frequently Asked Questions (FAQ)
Which method is most “accurate”?
Mathematically, all are accurate. The “best” method is the one your local community uses to ensure unity in worship .
Why do mosque times have “Safety Minutes”?
Mosques often add 2-5 minutes (Ihtiyat) to calculated times as a buffer for atmospheric changes or observation errors .
Does my method affect Ramadan fasting?
Yes. Your Suhoor ends at the start of Fajr. Using a 15° method instead of an 18° method could mean eating 15-20 minutes longer than your neighbors .
