Helmet sizing
Helmet size for a 4 year old
A typical 4 year old's head measures about 50.5 cm (19.9 in) around, which is usually a XS (toddler) helmet. Measure 1 in above the eyebrows and buy a CPSC-certified helmet whose own fit range covers the number.
At 4, kids are usually riding 3-wheel scooters, balance bikes and first pedal bikes. That decides the certification: CPSC is required on every US bike helmet.
Head size around age 4
| Age | Typical head | Usual size |
|---|---|---|
| 3 | 49.5 cm / 19.5 in | XS (toddler) |
| 4 | 50.5 cm / 19.9 in | XS (toddler) |
| 5 | 51 cm / 20.1 in | S |
Measure and convert
Helmet sizeUpdates as you type
Size XS (toddler) (50.5 cm / 19.9 in)
- Certification for this riding
- CPSC
- Fit check
- Two fingers above the eyebrows, straps in a V under the ears, one finger under the chin strap
- Helmets here whose stated fit covers 51 cm
- 5
Between sizes, choose the smaller one if its range covers you and tune with the dial. Replace any helmet after a crash.
Helmets whose stated fit covers 50.5 cm
| Helmet | Price | Fit | Certification stated |
|---|---|---|---|
| Schwinn Classic Bike Helmet for Kids | $17.89 | 48-52 cm | CPSC |
| Bell Disney Princess Toddler & Kids Bike Helmet | $19.96 | 48-52 cm | CPSC |
| MOUNTALK Kids Bike Helmet | $19.97 | 46-54 cm | CPSC |
| Bell Spiderman Spidey Eyes Toddler Helmet | $21.59 | 48-52 cm | CPSC |
| DARME Kids Bike Helmet Set | $23.50 | 48-57 cm | check listing |
| WayEee Kids Bike Helmet Set Skateboard Knee Pads | $23.99 | 48-54 cm | check listing |
| WayEee Kids Bike Helmet Set Skateboard Knee Pads | $23.99 | 48-54 cm | check listing |
| Bimalsic Toddler Bike Helmet Adjustable Dial Fit -12 Vent for 2-6 Year | $23.99 | 45-54 cm | CPSC |
| BELL Marvel Spiderman Hero Helmet | $24.96 | 50-54 cm | CPSC |
| Odoland Kid's Bike Helmet Adjustable Fits 48-54cm | $27.05 | 48-54 cm | CPSC |
| Besttravel Kids Bike Helmet | $27.88 | 48-54 cm | check listing |
| ZLEIOUY Color Gradient Adjustable Bike Helmet with Knee and Elbow Pads | $29.59 | 48-58 cm | check listing |
| HocIece Kids Bike Helmet Set Adjustable Helmet | $29.99 | 47-59 cm | check listing |
| JEEFREE Adjustable Color Gradient Toddler Kids Bike Helmet | $31.58 | 48-62 cm | check listing |
Helmets for a 4 year old, plus pads
Prices change often; the button shows today's price on Amazon.
Other ages
- Helmet size for a 1 year old
- Helmet size for a 2 year old
- Helmet size for a 3 year old
- Helmet size for a 5 year old
- Helmet size for a 6 year old
- Helmet size for a 7 year old
- Helmet size for a 8 year old
- Helmet size for a 9 year old
- Helmet size for a 10 year old
- Helmet size for a 11 year old
- Helmet size for a 12 year old
Questions riders ask
What size helmet does a 4 year old need?
Most 4 year olds measure about 50.5 cm around the head, a XS (toddler) in most brands, but heads vary by 2 to 3 cm either way at every age. Wrap a soft tape measure about 1 in above the eyebrows and over the widest part at the back, then choose the helmet whose stated fit range covers the number, ideally near the middle of it.
How should a kids helmet fit?
Two fingers of forehead above the eyebrows, side straps forming a V just under each ear, and no more than one finger under the buckled chin strap. Tighten the rear dial until the helmet does not move when the child shakes their head. If it rocks back to show the forehead, it is too big or the front straps are loose.
Does a 4 year old need a skate helmet or a bike helmet?
At 4, a CPSC-certified bike helmet covers 3-wheel scooters, balance bikes and first pedal bikes. Skate-style dual-certified helmets (CPSC plus ASTM F1492) become worth it once the child starts spending time at a skatepark, usually from about 8.
Wear a helmet every ride, and check your state and city rules on age, speed and where scooters may ride. This page is researched guidance, not professional, legal or medical advice. Specifications come from each product listing and can change; confirm on the listing before you buy.