I was trying to find a halloween costume for my son who is 6 yrs old. Looking at the waist size description I ordered a small thinking that since my waist is a 29, a 31" waist (when stretched) would more than likely fit okay if not a bit big. After tacking on another $19 for expediated shipping in hopes that it would arrive before halloween so that if it didn't work I could find another costume, it arrived the day before halloween, a week after I ordered it and it was WAY too small. The costume is darling, well made for a costume, but runs way too small.