Choose size based on the child’s measurements in width: waist width and hip width. If the child’s height doesn’t correspond to the same size, I recommend that you lengthen/shorten or blend sizes. For example, if the child is 55 cm in waist width and 62 cm in hip width (size 110) but only 98 cm tall - choose size 110 and shorten the front and back to size 98. See the guide in the Instructions.