I'm a 15 year old boy I live with my dad and want to live with my mom that I only see every other weekend not including Sunday.Because my dad is the biggest jerk ever, to prove my point he has been married 5 times,and working on the fifth. He always gripes at me and won't let me do anything. And his punishments are way to harsh like today I had to run 15 laps up and down our half a mile long road in front of our house. And if I stop he yells and gives me more laps and then when I got done he wiped me 7 or 8 time with his belt. All just because I broke my window screen and on top of all that I work out every day and I just happened to work out legs today and they were really sore when he made me run. So when and at what age can I choose to live with my mom and he can't stop me.

At 18. A minor cannot choose which parent to live with. That decision is made by a family court judge.

What has to happen is your mom needs to petition the court for a change of custody. The judge will then listen to your preferences and make a decision on what is in your best interests.

I don't really see a lot of good reasons to switch from what you have said. But there may be more. Depending on your state the judge may put more weight on your desires.