The five daily prayers (salah) are each tied to a window defined by the sun. The windows tile the day in order — each prayer starts where its definition begins and ends where the next phase arrives.
| Prayer | Window starts | Window ends |
|---|---|---|
| Fajr (dawn) | Morning twilight — first light (true dawn) | Sunrise |
| Dhuhr (midday) | Just after the sun passes its peak (solar noon) | Start of Asr |
| Asr (afternoon) | Shadow reaches the defined ratio (1× or 2× by school) | Sunset (Maghrib) |
| Maghrib (sunset) | Sunset | Disappearance of evening twilight (start of Isha) |
| Isha (night) | End of evening twilight | Midnight / dawn (conventions vary) |
Notes that matter in practice
Sunrise is a boundary, not a prayer — it ends Fajr's window, which is why timetables always list it alongside the five. Maghrib's window is the shortest in feel: it starts exactly at sunset, and during Ramadan it is also the moment the fast breaks (iftar). Fajr's start is the fasting boundary — the fast begins at Fajr, so Ramadan schedules watch the method (twilight angle) behind the printed Fajr time closely. Jumu'ah, the Friday congregational prayer, replaces Dhuhr on Fridays at the mosque's announced time — typically early in Dhuhr's window.
Travelers and shift workers should consult a scholar or their local mosque for the dispensations that apply to them; this page is a reference for the standard windows that the calculator on this site computes.