What percent of people have one foot larger than the other and what side is usually larger?

Common. : I do not have data to describe the exact incidence of this happening, but slight asymmetry is pretty common between both the left and right side. I do not know which side is more common to have this occur.

Interesting question: It's common to have some mild asymmetry. I guess, since there are more right handed and right legged people on earth, the right side would usually be the larger one. Keep in mind that this is gradual. If all of a sudden you see one leg becoming bigger than another, go see your doctor right away because this is abnormal and might signal a blood clot or lymph obstruction.