But before your preschooler goes cruising the neighborhood, it's important she put on a helmet first. More than 200 kids each year are killed in bicycle-related accidents, and almost 60 percent of those deaths are due to head injuries. To find a helmet that fits properly, you must know the circumference of your child's head. Using a tape measure, start at the middle of your child's forehead and bring the measure around, making sure that it goes over the most prominent rear portion of her skull. Take this measurement with you when you go shopping.
Manufacturers use head circumference as the basis for their sizing system.
Make it snug. If it's too big, it will slip around, offering little protection. Use the pads that come with the helmet to make sure that it fits securely. If you have used all four of the thickest pads and the helmet is still not snug, go back to the store and exchange it for a smaller size. Set a good example.