Our children and juvenile short sleeve cotton shirt make our school boys and girls have cool and beautiful summer,bring more confident to our kids.usually if your kids are between 4 and 6 years old, you buy size 4 or size 6,if your kids are between 6 and 8 years old, you buy the size 6 or size 8,so similar age get similar size, also consider the kid body size and make choice by the accordingly adjustment.