How to Size a Kids' Bike Helmet (With Photos)

Helmet sizing trips up almost every first-time buyer because helmets use centimeters, children grow constantly, and the fit rules differ from hats. Sixty seconds and a measuring tape solve it permanently.

Step 1: measure head circumference — wrap the tape just above the eyebrows and ears, around the widest back point. Note the centimeters. Step 2: match to helmet range: 46–51 cm = toddler XS (the XJD Kids Bike Helmet & Protective Gear Set – Pink toddler line); 48–55 cm = kids; 52–58 cm = youth.

Measure above the brows, buy by centimeters, never by age.

See the XJD Kids Bike Helmet & Protective Gear Set – Pink for current colors and sizing.

Step 3: fit-test in order — shake test (helmet moves with the head, not around it), two-finger brow test (no more than two fingers above the eyebrows), and strap test (V under the ears, one to two fingers under the chin buckle). Step 4: adjust the rear dial until snug — the dial does the fine sizing the shell can't.

Re-measure every six months through the growth years; the classic failure is a helmet that fit at five being worn at seven. Between sizes, size up only if the dial can still snug it down properly. And when the child picks the color themselves, you never have to fight the helmet battle — the helmet is theirs.