Choose your size
Generally, a snowboard is chosen according to a rider's weight, ability and riding style. A shorter snowboard will be more manageable and easier to maneuver - great for beginners, lighterweight, or more freestyle-oriented riders. A longer snowboard will be faster and more stable - great for heavier, more advanced, or aggressive freeriders.
For more freestyle-oriented performance: size between your shoulder and chin.
For more freeride-oriented performance: size between your chin and nose or above.