Every child is different, which makes it difficult to order the correct size without trying on. We have a measurement guide to help make sure you order the right size. Measure and see! T1: size 86-92. T2: size 92-98. T3: size 98-104. T4: size 104-110. T5: size 110-116. T6: size 116-124. T7/8: size 128-134.