The decision depends on your kid’s physical ability and body size. The size of kick scooters is related to their wheel size. For instance, kick scooters with 125mm, 100mm, and 120mm wheels are considered small. Models with 145mm and 180mm wheels are considered medium, while scooters with 200mm and 205mm wheels are considered large. You can also find extra-large scooters with 230mm wheels.