Determining the proper snowboard size depends on several factors, including the rider's height, weight, skill level and riding style. Based purely on physicality, the length of a snowboard usually depends on the height of the rider. Typically, a properly sized snowboard should have a length that comes up to the rider's chin when stood on its end. The width of a snowboard should be wide enough that the rider's boots should barely hang over the edges of the board.
Snowboard boots that hang over the edges of the board offer improved leverage and control when carving in the snow. However, when boots hang too far over the edges of a board, they can clip the snow on turns and cause dangerous falls, making it vital that boards have the proper width for a rider.
Riders with better skills can choose stiffer boards as well as boards that better fit their riding style. For example, riders that snowboard in powder or simply enjoy riding at high speeds typically prefer longer boards that pick up speed easily and offer excellent stability and balance. These boards typically come up to the rider's nose when stood on end.
Riders that like park style riding and performing acrobatic tricks usually prefer shorter boards that are lighter, offer better maneuverability and spin more easily than longer boards. These boards, on end, come to somewhere around the rider's shoulder and the bottom of their chin.