It depends of the day, but, generally:
On weekdays I study for about 3-5 hours. On weekends I study less, for about 1-2 hours.
That's because I only can play the piano when my parents aren't home, because they don't like the sound and, with complaints every moment, I just CAN'T STUDY! So, I just can play the piano on weekdays in the afternoon, and on weekends at moments I'm able to play at sparse moments.
There was a time that I studied for about 8-9 hours a day because I was studying the first movement Beethoven's Sonata Op.2/1... In one week, I got it but it's still not perfect. ^^ After this, I chose Pathetique Sonata's 1st Mov., and I took about month and a half... :x Now I'm stopped but I want to study more sonatas... =D