marla singer says on 14/Feb/12
Emma Watson looked a bit taller than J.K. Rowling lately, but it could be thanks to higher platforms hidden by long dresses. Here they wore similar heels (3") Click Here Joanne has a straight posture, while Emma is lowering on her knees but is standing closer to the camera so they are probably same height.
I think Joanne is in the 5'3 mark (158-160) and Emma around 5'3 and 5'4 as well (160-162).

Nicole G says on 1/Jan/12
She seems about the same height as Emma Watson and Daniel Radcliff in pictures, so 5'5" seems about right, maybe .75 shorter, not even the full inch