How far apart should the feet be while standing (qiyam) during prayer?

Since there is no authentic and explicit hadith regarding the distance between the feet while standing (qiyam) in prayer, Islamic scholars have expressed different opinions on the matter.

According to the Hanafi school, the feet should be kept about four fingers apart during qiyam. (Shurunbulali, Maraqi al-Falah, 98) According to the Shafi'i school, the feet should be about a handspan apart. (Zakariyya al-Ansari, Asna al-Matalib, 1/146) According to the Maliki and Hanbali schools, the feet should not be spread excessively nor should they be completely joined together. (Zuhayli, al-Fiqh al-Islami, 2/881-882)

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu