My son needed black pants for a choir show for CHristmas. I wanted something a little different than your average black dress slacks, so I bought these.
My son is hard to find pants for because he is tall and slim. I bought these and they were a size 12, which is what he needs for length (size 10 for waist). They fit perfect. He looked quite sharp standing among his choir mates.

I would reccomend going up a size if your child is not slim.