Squats? how low to go?

i do low bar squats and try to do it with good form
now i would like to know the Difference between hip parallel and knee parallel?
hip is lower but how much
knee i understand is were the top part of your quad is parallel to the ground
how much lower is hip parallel
i think hip parallel is where your hams are resting on your calves but i'm not positive
i know i can;t go ATG with low bar squat so i'm trying hip parallel but i would like to know exactly where that is

taylor2012-02-27T18:09:13Z

Place your feet shoulder width apart and squat down to where your upper legs/ thighs, are just below parallel to each other. Hold for a brief second and then rise, and repeat.