This size chart is based on the the size of the finished kigu and not the size of the person underneath. I've done it this way to give the commissioner the freedom to choose how large the kigu is based on what seems most comfortable, and not what I decide is best. For example, if you want a baggier kigu, you can pick a larger size! Of course, these sizes seem a little slim to me, so if you are looking for something a little larger don't hesitate to ask!