You open two prayer apps and one says Asr is at 16:45, the other at 17:35. Neither is broken. They're using two different — and both classically valid — definitions of when Asr begins.
The shadow-length rule
Classically, Asr begins when an object's shadow reaches a certain multiple of its height (beyond the small shadow it casts at noon):
- Shafi'i, Maliki & Hanbali view: Asr begins when the shadow equals one object-length. This gives the earlier Asr time.
- Hanafi view: Asr begins when the shadow equals two object-lengths. This gives the later Asr time.
The gap between the two is typically 40–70 minutes, varying with season and latitude. Every serious prayer app must therefore ask which madhhab you follow — an app that doesn't ask is silently choosing for you.
Which Asr setting should I choose?
Follow the school you already follow in the rest of your practice, or the timetable of your local mosque. As a rough guide: Muslims with roots in Turkey, the Balkans, Central and South Asia commonly follow the Hanafi school; those from the Arab world, East Africa, and Southeast Asia commonly follow schools using the earlier Asr. When in doubt, ask your imam — and note that praying Asr after the two-shadow mark satisfies both definitions.
Setting your Asr time correctly on iPhone
Do it with Vaktim (free, iPhone)
- During onboarding — or anytime in Settings → Prayer Calculation → Madhhab — choose:
- Hanafi — "Asr begins at the later time"
- Shafi'i — "Asr begins at the earlier time"
- Your daily timetable, the Asr notification, and your widgets all update instantly to the chosen definition.
- If your mosque's Asr still differs by a couple of minutes, fine-tune it with Prayer Time Adjustments (±30 minutes per prayer).
Does madhhab affect the other four prayers?
For calculation purposes, no — Fajr, Dhuhr, Maghrib, and Isha are computed the same way for both settings. The differences that do exist for Fajr and Isha come from the calculation method (horizon angles), not the madhhab — that's a separate setting explained in our Diyanet prayer times guide.
Until when can I pray Asr?
The Asr window runs until Maghrib (sunset), though it is recommended to pray before the sun weakens and yellows. Vaktim's live countdown shows exactly how long remains until the next prayer, so you always know how much of the window is left.