Reference: Fatāwā Muḥammadiyyah, Vol. 1, p. 453
❖ Question
Can one always perform only four Rak‘ahs of Tahajjud?
❖ Answer
Al-ḥamdu lillāh, waṣ-ṣalātu was-salāmu ʿalā Rasūlillāh, ammā baʿd:
The Messenger of Allah ﷺ usually performed eleven Rak‘ahs in Tahajjud, which included eight Nafl and three Witr, and this is the Sunnah method.
At times, the Prophet ﷺ prayed seven Rak‘ahs and on other occasions nine Rak‘ahs, as mentioned in Tirmidhī Sharīf:
(Bāb mā jāʾa al-witr, Sunan at-Tirmidhī with Tuḥfat al-Aḥwadhī, Vol. 1, pp. 337–338)
Conclusion:
The Sunnah method is to pray eleven Rak‘ahs (eight Tahajjud + three Witr), though at times the Prophet ﷺ performed seven or nine Rak‘ahs.
ھذا ما عندي واللہ أعلم بالصواب
