We used to estimate the time that the Messenger of Allah (may Allah's peace and blessings be upon him) would stand when performing the Zhuhr and the ‘Asr prayers. We estimated that the time he stood in the first two Rak‘ahs of the Zhuhr prayer as the being the time taken to recite Sūrat As-Sajdah and it would be half of that time in the last two Rak‘ahs

This noble Hadīth clarifies the duration of standing in the Zhuhr and ‘Asr prayers. The duration of standing in the first two Rak‘ahs of the Zhuhr prayer is equal to the duration of reciting thirty verses; the time taken to recite Sūrat As-Sajdah, and the last two Rak‘ahs take about half that time; the time taken to recite fifteen verses.

The ‘Asr prayer is shorter than the Zhuhr prayer, as the first two Rak‘ahs last long enough to recite fifteen verses and the last two Rak‘ahs take half that time; the time taken to recite seven to eight verses.