Fasting during Ramadan is an obligatory monthly duty for every Muslim who is of sound mind and has reached puberty. Those with religiously valid excuses—such as illness, travel, menstruation, or postpartum bleeding—as well as the elderly who are unable to fast are exempt from this obligation under certain conditions.

Intentionally eating, drinking, or engaging in sexual intercourse breaks the fast; this requires both making up the missed fast and fasting continuously for 60 days as expiation. However, eating or drinking while forgetting that one is fasting does not break the fast; this is considered a favor from Allah to His fasting servant.

The pre-dawn meal may be eaten until the time of imsak, which marks the second dawn. When the call to prayer begins at the time of imsak indicated in the calendar, eating and drinking must cease immediately, and one must begin fasting with the intention to do so.

Those who travel a distance of at least 90 km —which is considered a journey for religious purposes—or those who fear that their illness will worsen if they fast may postpone their fasts. Patients with no hope of recovery and the elderly who are unable to fast must pay a compensation equivalent to feeding one poor person for each day they are unable to fast.

Praying the Tarawih prayer is a strongly recommended Sunnah specific to the nights of Ramadan. This prayer, which began to be performed in congregation and in sets of 20 rak’ahs in the 14th year of the Hijrah at the instruction of Umar ibn al-Khattab (may Allah be pleased with him), has been passed down to the present day in this manner.