What is Imsak, and when must I stop eating?

7 November 2026

The fast starts at Fajr: true dawn, when the first light spreads along the horizon. Imsak is a time printed a few minutes earlier, often 10, as a safety margin. It is a precaution, not the start of the fast.

Why the margin exists

Nobody can see the exact second of dawn from a kitchen. A timetable is a calculation, and calculations differ by a minute or two. Stopping a little early makes sure your last bite is before dawn, not after it.

If you are not sure dawn has come

What breaks the fast is eating after dawn, not after Imsak. Ayatollah al-Sistani's rulings set out what happens when you are unsure:

• If you doubt whether dawn has come, you may still eat or drink, even before checking (ruling 1662).
• If you eat without checking and it turns out dawn had already come, you make up that day later. No kaffarah is due (ruling 1657).
• If you did check, could not tell, ate, and it later turns out dawn had come, no make-up is due (ruling 1661).

His rulings set no Imsak time of their own. The margin keeps you out of that doubt altogether. If your marja' asks for a margin before dawn, follow it.

What to do in practice

• Plan to finish suhur by Imsak.
• If you are still eating after Imsak but before Fajr, your fast is not broken.
• Once Fajr has come, stop, even mid-meal.
• Pray Fajr once its time has come, not at Imsak.

How the app shows it

Shia Namaz can show Imsak as its own row before Fajr. Turn it on in Settings and choose how many minutes before Fajr it falls; it starts at 0, the same as Fajr, until you pick a margin. Fajr itself is the sun 16° below the horizon with Qom, the default, or 17.7° with Tehran. This site has the same option under Calculation settings, "Include Imsak".

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Next guide: why Shia Eid is sometimes on a different day →