Snowboard bindings coincide with boot sizes which are true to shoe size. Kid's bindings usually consist of boot sizes 1-5 or 5-7. For Men's, Smalls usually go from 5-7, Mediums 7-9, Larges 10-12, and Extra Larges 12+. In Women's, Smalls usually go from 5-8, Mediums from 8-10 and Larges 10+.
The size of snowboard bindings can vary quite a bit from brand to brand though, so be sure to check our brand specific size charts in our Snowboard Binding Sizing Guide.