"The Messenger of Allah [SAW] said: 'The Izar should come to the middle of the shins and the calf. If you insist, then a little lower, and if you insist, then a little further down, but the Izar has no right to (come to) the ankle." This is the wordings of Muhammad.  

قَالَ رَسُولُ اللَّهِ ﷺ مَوْضِعُ الإِزَارِ إِلَى أَنْصَافِ السَّاقَيْنِ وَالْعَضَلَةِ فَإِنْ أَبَيْتَ فَأَسْفَلَ فَإِنْ أَبَيْتَ فَمِنْ وَرَاءِ السَّاقِ وَلاَ حَقَّ لِلْكَعْبَيْنِ فِي الإِزَارِ وَاللَّفْظُ لِمُحَمَّدٍ