Methodology and Prayer Time Sources

Methodology and Prayer Time Sources

We calculate prayer times astronomically using the Umm al-Qura method, city coordinates, and time zone data.

Calculation Methodology

We calculate the five prayer times from the sun's position relative to the horizon. The Umm al-Qura method uses specified angles for Fajr and Isha, with calculation details listed below.

Umm al-Qura Methodology

• Fajr: 18.5 degrees below the horizon (with special adjustment for high-latitude regions)
• Sunrise: Moment the sun's disk appears above the horizon
• Dhuhr: Moment the sun crosses the meridian (highest point in the sky)
• Asr: When an object's shadow equals its length plus the shadow at noon (Hanafi school: twice the length)
• Maghrib: Moment the sun's disk disappears below the horizon
• Isha: 17 degrees below the horizon (or 90 minutes after Maghrib in some applications)

Data Sources

The displayed data relies on the following sources:

• Saudi Geological Survey tables for comparison in Saudi Arabia
• Internal astronomical calculations using Umm al-Qura methodology for cities outside Saudi Arabia
• Geographic coordinate databases for cities (GeoNames and others)
• Time zone data from the IANA Time Zone Database

Internal Comparison

To verify calculation accuracy, periodic internal comparisons are performed between:

• Internal calculation results using Umm al-Qura methodology
• Aladhan library (as a reference source for comparison only)
• Published Saudi Geological Survey tables

The Aladhan library and Umm al-Qura tables are used only for internal comparison; their results are not displayed directly. The displayed times come from our internal calculation using the Umm al-Qura method.

Coordinates and Time Zones

We use each city's coordinates (latitude, longitude, and elevation) and time zone data. Daylight saving changes follow the available time zone data.

Methodology Updates

The methodology and data sources are reviewed periodically. Any material change to the calculation methodology or sources will be announced on the updates page with an explanation of the reasons and expected impact on prayer times.