I want to know the percentage of my body fat but can't figure out how to find out how
You can find your % in 3 ways.
1. Hydrostatic weighing(underwater)(good luck finding one though--- some colleges/universities that have an exercise science or health related program may have one.
2. Skin calipers(skin folds)-- which are accurate(as Rappa said) provided it is done by someone that was trained to do so(most personal trainers can do them.
3. The electic scales or hand held measures(which are fairly accurate if the other 2 are not available)
You can do it on websites.... where you input your body statistics and the calculator calculates it for you.. its an approximation based on body measurements... but its good enough