These leggings run small with an elastic waistband. I suggest ordering one size larger than you normally wear.
 The models are wearing medium in the photos.
 the small = xsmall, 00-0
 medium = small, 2-4 years
 large = medium, 5-6 years
 x-large = large 7-8 years
 Fabric: 20% Spandex, 80% Nylon