Frequently Asked Questions - Search for standards

To determine Isha and Fajr calculations, one needs to calculate the time when the sun is at a certain distance below the horizon. The twilight angle is used for this purpose and it is defined as the angle in degrees of the sun below the horizon, when total darkness begins or ends.
Some organisations use a fixed time after Maghrib to determine the start of Isha time The following standards exist for determining Fajr and Isha times:

Egyptian General Authority of Survey:

Region	Africa, Syria, Iraq, Lebanon, Malaysia, parts of the USA
Fajr – twilight angle	19.5
Isha – twilight angle	17.5

Islamic Society of North America (ISNA):

Region	Parts of the USA, Canada, parts of the UK
Fajr – twilight angle	15
Isha – twilight angle	15

Islamic Organisations Union of France:

Region	France
Fajr – twilight angle	12, 15 or 18
Isha – twilight angle	12, 15 or 18

Majlis Ugama Islam Singapura:

Region	Singapore
Fajr – twilight angle	20
Isha – twilight angle	18

Muslim world league:

Region	Europe, Far East, parts of the USA
Fajr – twilight angle	18
Isha – twilight angle	17

Umm Al Qura:

Region	The Arabian Peninsula
Fajr – twilight angle	18.5
Isha – twilight angle	90 minutes after Maghrib (120 minutes during Ramadan)

University of Islamic sciences, Karachi:

Region	Pakistan, Bangladesh, India, Afghanistan, parts of Europe
Fajr – twilight angle	18
Isha – twilight angle	18