Visit the breakfast television link to find more about how to fit and size bikes and helmets.
When younger your child should have their feet flat to the ground and able to push off of toes. When they get older, their feet should be on the tips of their toes.
Y shape around ears, 2 fingers from eyebrows to the top of their head, 2 fingers under strap and the helmet fits snug and is not moving around on your child's head. It is important to have a properly fitted helmet to ensure that it protects your child's head in the case of a crash.