Fitting a Bike Helmet

​​​The best way to fit a helmet is to measure the child’s head around the widest part just above the eyebrows and ears.

Helmets should have a label indicating what size they are. Choose the smallest helmet that will fit the child.

First put on the helmet so it is level on the child’s head and— if it slides around or moves side to side, insert helmet sizing pads.

Determining Proper Helmet Size

Helmet size varies based on different manufacturers. The following provides a general idea. For more details go to the Bicycle Helmet Safety Institute or go to the manufacturer website.

Hat SizeHead Circumference​​​​​Approximate Helmet Size
6 ½20 ½ inchesToddler
6 ⅝20 ⅞ inches530 Small
6 ¾21 ¼ inches540 Medium
7 ¼22 ¾ inches578 Large​

Adjust the Straps

  • Eyes: The child should be able to see the front edge of the helmet.
  • Ears: The sliders should be moved up to just under the ear lobes.
  • Mouth: The chin strap should fit snugly enough that opening the mouth widely will move the helmet.
 Follow the diagrams for fitting a helmet:
Helmet fit diagram


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