Kids Helmet Size by Head Circumference
Find kids helmet size by head circumference with bike and ski helmet fit checks, age guidance and links to helmet and kids size converters.
Kids helmet sizing should be based on head circumference, not age alone. A properly fitted helmet protects only when it sits level, stays stable and matches the child's current head size. Use the Helmet Size Converter to match circumference to common helmet labels.
Measure Around the Widest Point
Wrap a soft tape around the widest part of the child's head, just above the eyebrows and ears. Keep the tape level and snug. Repeat the measurement once to confirm accuracy, then compare the result with the helmet chart instead of choosing by age.
Check Bike and Ski Helmet Fit
Bike and ski helmets may use similar circumference ranges, but padding, ear coverage and shell shape differ. Test the helmet with straps adjusted. It should not tilt back, cover the eyes or move independently from the head during gentle shaking.
Track Growth Regularly
Children's head size changes more slowly than shoe or clothing size, but it still changes. Use the Kids Size Converter for clothing and shoe growth checks, and remeasure helmet circumference each season or before a new sport.