Different Islamic authorities use varying mathematical formulas to calculate prayer times based on the sun's position. Each method has slight variations in angles for Fajr and Isha prayers. Choose the method most commonly used in your region or by your local mosque.

Standard: Used by Shafi, Maliki, and Hanbali schools. Asr prayer begins when shadow length equals object height.

Hanafi: Asr prayer begins when shadow length equals object height plus original shadow. This results in a later Asr time.