Rider-matched picks
Size-matched helmets picks for 4 year olds, with fit and feature priorities curated for how 4 year olds actually ride.
Open the helmets calculatorFour-year-olds are often ready to move from a balance bike to a pedal bike, or from training wheels to riding independently. Most children this age fit a 12" or 14" wheel bike, depending on their height. The right bike allows your child to sit on the saddle and touch the ground with the balls of their feet. If your child has been riding a balance bike, they may be ready to go straight to a pedal bike without training wheels — many 4-year-olds make this jump successfully. A coaster brake (pedal backward to stop) is still the easiest braking system for this age, though some children can begin learning hand brakes. Bike weight remains important: a too-heavy bike makes pedaling and balancing harder.
Measure head circumference at the widest point across the forehead. Most brands size: XS (50–53 cm), S (53–56 cm), M (56–59 cm), L (59–62 cm), XL (62+ cm). Kids helmets typically start at 47–50 cm. Always try before buying; fit varies by brand.
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Giro
S 51–55 cm, M 55–59 cm, L 59–63 cm
Bell
S 52–56 cm, M 56–60 cm, L 60–64 cm
Smith
S 51–55 cm, M 55–59 cm, L 59–63 cm
Poc
S 50–54 cm, M 54–58 cm, L 58–62 cm
Lazer
S 50–54 cm, M 54–58 cm, L 58–62 cm
Kask
S 50–54 cm, M 54–58 cm, L 58–62 cm
Troy Lee Designs
S 53–56 cm, M 56–59 cm, L 59–62 cm
Abus
S 52–58 cm, M 58–64 cm
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